Image formation apparatus

ABSTRACT

An image formation apparatus is disclosed which includes, within an enclosure configured by a pair of substrates placed face to face and an external frame placed between the substrates, an electron source placed on one of the pair of substrates, an image formation material placed on the other substrate, and spacers placed between the substrates, characterized in that the spacers and the external frame is conductive and device is provided for electrically connecting the spacers and the external frame so that the equipotential surfaces between the spacers and the external frame are quasi-parallel when driven.

RELATED APPLICATIONS

This application is a divisional of application Ser. No. 11/514,196,filed Sep. 1, 2006, which is a divisional of application Ser. No.10/931,094, filed Sep. 1, 2004, now U.S. Pat. No. 7,157,850, which is adivisional of application Ser. No. 09/705,957, filed Nov. 6, 2000, nowU.S. Pat. No. 6,879,096, which is a continuation of internationalApplication No. PCT/JP2000/01347, filed Mar. 6, 2000. The presentapplication claims priority benefit of Japanese Patent Applications Nos.11-103035, filed Mar. 5, 1999, and 11-098232, filed Apr. 5, 1999. Theentire disclosure of each of the mentioned U.S., international andJapanese applications is hereby incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an image formation apparatus providedwith an electron beam source substrate and a light-emitting displayplate placed face to face that forms an image by supplying electronsemitted from the electron beam source substrate according to imageinformation to the light-emitting display plate.

BACKGROUND ART

Image display apparatuses equipped with an electron emission cathode ofvarious configurations are conventionally proposed. As an example, theone having a structure whose cross-sectional view is shown in FIG. 1 isknown. The display apparatus shown in FIG. 1 is a full-color displayapparatus and has multiple stripe-shaped anode electrodes 11106 providedon the inner surface of an anode substrate 11101 and on the anodeelectrodes 11106 are formed surfaces on which fluorescent materials thatemit R, G and B lights are sequentially deposited. On the other hand, ona cathode substrate 11102 facing the anode substrate 11101 are providedFEC arrays 11105 made up of multiple electron emission cathodes (FEC).From these FEC arrays 11105, electrons are emitted in an electric fieldand these electrons emitted are captured by the anode electrodes 11106and electrons are supplied to fluorescent materials deposited thereon,thus emitting light. Emission of electrons is generally controlled bythis apparatus on the FEC arrays 11105 side and electrons emitted fromthe FEC arrays 11105 are emitted toward the anode substrate 11104 placedopposite thereto at a predetermined distance kept by a column 11104.

To enable an operation involved in the above-described emission ofelectrons, this apparatus has a space formed to be in a predetermineddegree of vacuum between the anode substrate 11101 and cathode substrate11102 and the peripheral section of these substrates is sealed with asealing material 11103 to maintain this degree of vacuum.

The distance t between the anode substrate 11101 and cathode substrate11102 is set, for example, to several hundred μm and a voltage appliedto the anode electrodes 11106 is set, for example, to several hundred V.Moreover, the anode electrodes 11106 are connected to a display controlapparatus outside the display apparatus through anode leadingelectrodes, which are not shown in the figure, and a voltage is appliedto the anode electrodes 11106 by the display control apparatus atpredetermined timing. Furthermore, cathode electrodes and gateelectrodes of the FEC arrays 11105 are also connected to the displaycontrol apparatus outside the display apparatus through cathode leadingelectrodes and gate leading electrodes, which are not shown in thefigure and a voltage is applied to these electrodes by the displaycontrol apparatus at predetermined timing.

The electron emission section of the above-described image displayapparatus is formed by FEC arrays, but various configurations ofelectron emission devices placed on the electron emission section areproposed. For example, a surface-conduction electron emission device hasa simple structure and is easy to manufacture, and therefore has anadvantage of making it possible to arrange an array of multiple devicesover a large area. Therefore, various applications taking advantage ofthis feature are under study. An example of this is application to acharge beam source and an image formation apparatus such as a displayapparatus, etc. An example of arranging multiple surface-conductionelectron emission devices is an electron beam source obtained byarranging surface-conduction electron emission devices in parallel andarranging multiple lines with both ends of individual devices connectedwith a wire (e.g., the Japanese Patent Laid-Open No. 1-1031332 by theapplicant of the present application).

With regard to an image formation apparatus such as a display apparatus,a flat type display apparatus using liquid crystal device (LCD) has beenwidely spreading in recent years instead of a CRT-based one. However,the one using LCD is not of a self light-emitting type and has a problemof requiring a backlight, etc., and therefore a display apparatus of aself light-emitting type is needed.

A display apparatus combining the electron beam source with suchmultiple surface-conduction electron emission devices arranged andfluorescent materials that emit visible light by means of electronsemitted from this electron beam source can be relatively easilymanufactured even with a large screen and can furthermore provide anexcellent self light-emitting display apparatus with high-definitiondisplay, and therefore it is also desirable from the standpoint ofproviding a self light-emitting display apparatus.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide an image formationapparatus capable of satisfying large-screen requirements and having ahigh display-quality configuration.

In order to attain the above object, the present invention includes thefollowing characteristic aspects:

An aspect of the image formation apparatus of the present invention isan image formation apparatus comprising, within an enclosure configuredby a pair of substrates placed face to face and an external frame placedbetween the substrates above, an electron beam source placed on one ofthe pair of substrates, an image formation material placed on the othersubstrate and spacers placed between the substrates above, characterizedin that the spacers and external frame have conductivity and means forelectrically connecting the spacers and the external frame is providedso that the electric equipotential surfaces between the spacers and theexternal frame are quasi-parallel when the apparatus is driven.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising, within an enclosureconfigured by a pair of substrates placed face to face and an externalframe placed between the substrates above, an electron beam sourceplaced on one of the pair of substrates, an image formation materialplaced on the other substrate and spacers placed between the substratesabove, characterized in that the spacers and external frame haveconductivity, a quasi-equal electric potential V1 is applied to the topend of the spacer and the top end of the external frame when theapparatus is driven and a quasi-equal electric potential V2, which isdifferent from the potential V1 is applied to the bottom end of thespacer and the bottom end of the external frame.

An aspect of the electron beam source substrate of the present inventionis an electron beam source substrate comprising a plurality of electronemission devices wired in matrix on a substrate with a plurality ofrow-direction wires and a plurality of column-direction wires,characterized in that each of the plurality of electron emission devicesis surrounded by the row-direction wires and column-direction wires, andthe wiring width in a non-crossing area of the row-direction wires andcolumn-direction wires is wider than the wiring width in a crossing areaof the row-direction wires and column-direction wires.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising an electron beam sourcesubstrate equipped with a plurality of electron emission devices wiredin matrix on a substrate with a plurality of row-direction wires and aplurality of column-direction wires and an image formation material thatforms images by radiation of electrons emitted from the plurality ofelectron emission devices, characterized in that each of the pluralityof electron emission devices is surrounded by the row-direction wiresand column-direction wires, and the wiring width in a non-crossing areaof the row-direction wires and column-direction wires is wider than thewiring width in a crossing area of the row-direction wires andcolumn-direction wires.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising a substrate with a pluralityof wires connecting electron emission devices, a substrate with an imageformation material that forms images by radiation of electrons emittedfrom the electron emission devices, spacers placed between thesubstrates and getters, characterized in that the spacers are placed onthe wires and the getters are placed on the wires without the spacers.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising a substrate with a pluralityof wires connecting electron emission devices, a substrate with an imageformation material that forms images by radiation of electrons emittedfrom the plurality of electron emission devices, a plurality of spacersplaced between the substrates and getters, characterized in that theplurality of spacers is placed on the wires and the getters are placedon the wires between the plurality of spacers.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising a substrate with wiresconnecting electron emission devices, a substrate with an imageformation material that forms images by radiation of electrons emittedfrom the electron emission devices and spacers placed between thesubstrates, characterized in that the wires have an arch-shaped crosssection and the spacers are placed on the wires and the corner of theend face that has contact with the wire is rounded.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising a substrate with wiresconnecting electron emission devices, a substrate with an imageformation material that forms images by radiation of electrons emittedfrom the electron emission devices and spacers placed between thesubstrates, characterized in that the image formation material has anon-light-emitting material with an arch-shaped cross section and thespacers are placed on the non-light-emitting material and the corner ofthe end face that is in contact with the non-light-emitting material isrounded.

Another aspect of the electron beam source substrate is an electron beamsource substrate comprising a plurality of electron emission deviceswired in matrix on a substrate with a plurality of row-direction wiresand a plurality of column-direction wires, characterized in that thereis a potential regulation section in a non-crossing area of therow-direction wires and column-direction wires.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising an electron beam sourcesubstrate equipped with a plurality of electron emission devices wiredin matrix on a substrate with a plurality of row-direction wires and aplurality of column-direction wires and an image formation material thatforms images by radiation of electrons emitted from the plurality ofelectron emission devices, characterized in that there is a potentialregulation section in a non-crossing area of the row-direction wires andcolumn-direction wires.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising a first substrate with anelectron beam source and a second substrate with a fluorescent materialcoated with metal backing and non-light-emitting material placed facingthe electron beam source, characterized in that the fluorescent materialand the non-light-emitting material have a thickness different to eachother and means for applying a potential close to the potential appliedwhen the apparatus is driven to the side where the electron beam sourceis placed on the first substrate is provided on the side opposite to theside of the second substrate where the fluorescent material and thenon-light-emitting material are placed.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising a fluorescent material, ametal backing that covers the fluorescent material and a high-voltageleading terminal electrically connected to the metal backing, placed ona substrate, characterized in that a relay conductive film strip thatconnects between the metal backing and the high-voltage leading terminalis provided.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising an electron beam sourcesubstrate with an electron beam source, a fluorescent material, a metalbacking that covers the fluorescent material and a high-voltage leadingterminal electrically connected to the metal backing placed opposite tothe electron beam source substrate, characterized in that the imageformation substrate is provided with a relay conductive film strip thatconnects between the metal backing and the high-voltage leadingterminal.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising, an enclosure containing anelectron beam source substrate with an electron beam source, an imageformation substrate with an image formation material that forms imagesby radiation of electrons emitted from the electron beam source and acabinet with a support section for the enclosure, characterized in thatthe support section supports the electron beam source substrate withoutthe image formation substrate.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising a substrate with a pluralityof wires connecting electron emission devices, a substrate with an imageformation material that forms images by radiation of electrons emittedfrom the electron emission devices and a plurality of spacers placedbetween the substrates, characterized in that the plurality of spacersare placed on the wires discretely so that the number of wires betweenthe spacers falls within the range of 5 to 50.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising, within an enclosureconfigured by a pair of substrates placed face to face and an externalframe placed between the substrates above, an electron beam source andan image formation material that forms images by radiation of electronsemitted from the electron emission device, characterized in that theexternal frame is formed by die punching.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising, within an enclosureconfigured by a pair of substrates placed face to face and an externalframe placed between the substrates above, an electron beam source andan image formation material that forms images by radiation of electronsemitted from the electron emission device, characterized in that thecorners of the external frame have an arc shape inside and outside theenclosure and the arc shape has different curvatures inside and outsidethe enclosure.

An aspect of the electron beam source substrate is an electron beamsource substrate comprising electron beam emission devices, wiresconnected to the electron beam emission devices and getters,characterized in that the getters are placed on the wires and both thegetters and wires have an arc-shaped cross-section.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising a substrate provided withelectron beam emission devices, wires connected to the electron beamemission devices and getters, and an image formation material that formsimages by radiation of electrons emitted from the electron emissiondevices placed in an enclosure, characterized in that the getters areplaced on the wires and both the getters and wires have an arc-shapedcross-sectional shape.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising a display panel and ahigh-voltage power supply connected to the display panel, characterizedin that the high-voltage power supply is placed below the center ofgravity of the display panel.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus comprising a first substrate with afluorescent material and black material and a second substrate withelectron emission devices placed face to face, characterized in that theblack material is placed right above the electron emission section ofthe electron emission devices.

Another aspect of the electron beam source substrate of the presentinvention compressing:

a. A substrate;

b. An array of electrode pairs on a substrate configured by pairs ofdevice electrodes placed along a plurality of rows and a plurality ofcolumns;

c. A plurality of column wires on a substrate made up of column wires bymeans of screen printing, commonly connecting one of each electrode pairon the column provided on each column for each electrode pair;

d. A plurality of row wires insulated from the column wires on asubstrate made up of row wires by means of screen printing, commonlyconnecting the other of each electrode pair on the row provided on eachrow for each electrode pair;

e. A plurality of column terminal sections extended from the pluralityof column wires, by means of screen printing; and

f. A plurality of row terminal sections extended from the plurality ofrow wires, by means of screen printing.

Another aspect of the image formation apparatus comprising:

a. An electron beam source substrate comprising a first substrate, anarray of electrode pairs on the first substrate configured by pairs ofdevice electrodes placed along a plurality of rows and a plurality ofcolumns, an electron beam source placed between the pair of electrodes,a plurality of column wires on the first substrate made up of columnwires commonly connecting one of each electrode pair on the columnprovided on each column for each electrode pair, and a plurality of rowwires on the substrate that commonly connect the other of each electrodepair, insulate from the column wires, made up of a row wire of a wirewidth larger than that of the column wire provided for each electrodepair on each row;

b. An image formation substrate comprising a second substrate and animage formation material placed on the second substrate; and

c. Spacers inserted between the electron beam source substrate and theimage formation substrate and placed on the row wires.

An aspect of the image formation material of the present inventioncomprising:

a. An electron beam source substrate comprising a first substrate, anarray of electrode pairs on the substrate configured by pairs of deviceelectrodes placed along a plurality of rows and a plurality of columns,an electron beam source placed between the pair of electrodes, aplurality of column wires on the first substrate made up of column wirescommonly connecting one of each electrode pair on the column provided oneach column for each electrode pair, and a plurality of row wires on thefirst substrate that commonly connect the other of each electrode pair,insulate from the column wires, made up of a row wire of a wire widthlarger than that of the column wire provided for each electrode pair oneach row; and

b. An image formation material comprising a second substrate, an imageformation material of a rectangular shape having a vertical long side inthe observation direction placed on the second substrate along aplurality of rows and a plurality of columns and a shade material on thesecond substrate that covers the spaces between the rows and between thecolumns, characterized in that the image formation substrate has thedistance between the plurality of adjacent rows wider than the distancebetween the plurality of adjacent columns.

Another aspect of the image formation apparatus of the present inventioncomprising:

a. An electron beam source substrate comprising a first substrate, anarray of electrode pairs on the substrate configured by pairs of deviceelectrodes placed along a plurality of rows and a plurality of columns,an electron beam source placed between the pair of electrodes, aplurality of column wires on the first substrate made up of column wirescommonly connecting one of each electrode pair on the column provided oneach column for each electrode pair, and a plurality of row wires on thefirst substrate that commonly connect the other of each electrode pair,insulate from the column wires, made up of a row wire of a wire widthlarger than that of the column wire provided for each electrode pair oneach row; and

b. An image formation substrate comprising a second substrate, an imageformation material of a rectangular shape having a vertical long side inthe observation direction placed on the second substrate along aplurality of rows and a plurality of columns and a shade material on thesecond substrate that covers the spaces between the plurality ofadjacent rows and the distance between the plurality of adjacentcolumns, characterized in that the electron beam source is placed facingevery distance between the plurality of columns.

Another aspect of the image formation apparatus of the present inventioncomprising:

a. An electron beam source substrate comprising a first substrate, anarray of electrode pairs on the substrate configured by pairs of deviceelectrodes placed along a plurality of rows and a plurality of columns,an electron beam source placed between the pair of electrodes, aplurality of column wires on the first substrate made up of column wirescommonly connecting one of each electrode pair on the column provided oneach column for each electrode pair, and a plurality of row wires on thefirst substrate that commonly connect the other of each electrode pair,insulate from the column wires, made up of a row wire of a wire widthlarger than that of the column wire provided for each electrode pair oneach row; and

b. An image formation substrate comprising a second substrate, an imageformation material of a rectangular shape having a vertical long side inthe observation direction placed on the second substrate along aplurality of rows and a plurality of columns and a shade material on thesecond substrate that covers the spaces between the plurality ofadjacent rows and the distance between the plurality of adjacentcolumns; and

c. Spacers inserted between the electron beam source substrate and theimage formation substrate and placed on the row wires, characterized inthat the electron beam sources are placed facing every distance betweenthe plurality of columns.

Another aspect of the image formation apparatus of the present inventionis an image formation apparatus with image formation substrates placedface to face via spacers, characterized in that the spacers are placedon wires connecting the electron beam sources, coated with a conductionfilm that is electrically connected to the wires, and the height of thetop end of the conduction film is equal to or lower than the height atwhich the potential is higher by 2 KV than the electron beam sourcepotential in a potential distribution between the electron beam sourcepotential while the electron beam source is emitting electrons and theacceleration potential given on the image formation substrate side.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view showing a configuration of aconventional image display apparatus equipped with an electron emissioncathode;

FIG. 2 is a developed assembly view of an image formation apparatus, anexample of the present invention;

FIG. 3 is a developed assembly view of a display panel section used inthe image formation apparatus of the present invention;

FIG. 4 is a perspective view showing the display panel section shown inFIG. 3 as assembled;

FIG. 5 is a plan view of the face plate shown in FIG. 4;

FIG. 6 is an A-A cross-sectional view of FIG. 4;

FIG. 7 is a B-B cross-sectional view of FIG. 4;

FIG. 8 a is a top view of the display panel used in the image formationapparatus of the present invention viewed from the face plate side;

FIG. 8 b is a side view of the display panel shown in FIG. 8 a;

FIG. 9 a is a top view of another exemplar display panel used in theimage formation apparatus of the present invention viewed from the faceplate side;

FIG. 9 b is a side view of the display panel shown in FIG. 9 a;

FIG. 10 is a top view of an external frame provided with line gettersand peripheral supports used in the image formation apparatus of thepresent invention;

FIG. 11 is a cross-sectional view of another exemplar display panel usedin the image formation apparatus of the present invention viewed fromthe direction orthogonal to the longitudinal direction of a spacer;

FIG. 12 is a cross-sectional view of another exemplar display panel usedin the image formation apparatus of the present invention viewed fromthe direction parallel to the longitudinal direction of spacers;

FIGS. 13 a-13 e are process diagrams showing the procedure for formingelectron emission devices on an electron beam source substrate appliedto the image formation apparatus of the present invention;

FIG. 14 is a schematic diagram of the electron beam source substrateused in the image formation apparatus of the present invention;

FIG. 15 is a plan view of the face plate used in the image formationapparatus of the present invention viewed from the rear plate side;

FIG. 16 is an A-A′ cross-sectional view of FIG. 15;

FIG. 17 is a side view of a line getter;

FIG. 18 is a partially cut out perspective view of the image displaypanel section of the image formation apparatus, an example of thepresent invention;

FIG. 19 is a partial cross-sectional view of the display panel sectionof the image formation apparatus, another example of the presentinvention;

FIG. 20 is a partially cut out perspective view of the image displaypanel section of the image formation apparatus, another example of thepresent invention;

FIG. 21 is a partially cut out perspective view of the image displaypanel section of the image formation apparatus, another example of thepresent invention;

FIG. 22 is a partial cross-sectional view of the image display panelsection of the image formation apparatus, another example of the presentinvention;

FIG. 23 is a partial cross-sectional view of the image display panelsection of the image formation apparatus, another example of the presentinvention;

FIG. 24 is a partial cross-sectional view of the image display panelsection of the image formation apparatus, another example of the presentinvention;

FIG. 25 is a perspective view showing an arrangement structure ofspacers used in the image formation apparatus of the present invention;

FIG. 26 is a schematic view showing influences of spacers on emittedelectrons;

FIG. 27 is a partially cut out perspective view of the display panelsection of the image formation apparatus, another example of the presentinvention;

FIG. 28 is an A-A′ cross-sectional view of FIG. 27;

FIG. 29 is a partial cross-sectional view of the display panel sectionof the image formation apparatus, another example of the presentinvention;

FIG. 30 is a partial cross-sectional view of the display panel sectionof the image formation apparatus, another example of the presentinvention;

FIG. 31 is a schematic diagram to explain an allowable range ofpositional deviation of a spacer;

FIG. 32 is a schematic diagram to explain an allowable range ofinclination of a spacer;

FIG. 33 is a schematic diagram to explain an allowable range ofpositional deviation and inclination of a spacer;

FIG. 34 is a schematic diagram showing an example of an allowable rangeof positional deviation and inclination of a spacer;

FIG. 35 is a schematic diagram showing a shape exemplar spacer;

FIG. 36 is a schematic diagram to explain an allowable range ofpositional deviation of a spacer in the case of a stand having a flatsurface wider than the spacer;

FIG. 37 is a schematic diagram showing an example of assembling a spaceronto the face plate;

FIG. 38 is a schematic diagram showing a range of inclination of aspacer;

FIG. 39 is a schematic diagram showing a placement example of a spaceron a wire with a flat surface wider than the spacer;

FIG. 40 a is a cross-sectional view of a cathode substrate and anodesubstrate;

FIG. 40 b is a schematic diagram showing the shape of an electron beamon the anode substrate of the electron beam emitted from a surfaceconduction type electron emission device;

FIG. 40 c is an intensity distribution diagram showing an intensityvariation on an A-A′ cross-section of FIG. 40 b.

FIG. 41 a is a top view of the anode substrate;

FIG. 41 b is a side view of the interior of the image formationapparatus, another example of the present invention;

FIG. 41 c is a top view of the cathode substrate;

FIG. 42 a is a top view of the cathode substrate;

FIG. 42 b is a schematic view showing the shape of light emission(visible light) when an emitted electron beam hits the anode substratein FIG. 41 a.

FIG. 43 is a schematic diagram showing another exemplar trajectory areaof electrons;

FIGS. 44 a-44 c are schematic diagrams showing an example of thecross-sectional shape of a spacer;

FIGS. 45 a-45 c are schematic diagrams showing a macroscopic exemplararrangement of columnar spacers;

FIG. 46 is a schematic view of a vacuum container of a flat display;

FIG. 47 is an A-A cross-sectional view of FIG. 46;

FIG. 48 is a B-B cross-sectional view of FIG. 46;

FIG. 49 is a C-C cross-sectional view of FIG. 47;

FIG. 50 is a perspective view showing an exemplar spacer;

FIG. 51 is a cross-sectional view of the vacuum container of the flatdisplay viewed from a side;

FIG. 52 is a perspective view showing an exemplar spacer;

FIG. 53 is a schematic view showing an exemplar arrangement of spacers;

FIG. 54 is a schematic view showing another exemplar arrangement ofspacers;

FIG. 55 is a schematic view showing an exemplar frame material used inthe image formation apparatus of the present invention;

FIG. 56 is a schematic view showing another exemplar frame material usedin the image formation apparatus of the present invention;

FIG. 57 is a partially cut out perspective view of the image displaypanel section of the image formation apparatus, another example of thepresent invention;

FIG. 58 is an outlined cross-sectional view of an airtight containerused in the image formation apparatus of the present invention;

FIG. 59 is a developed perspective view of the airtight container usedin the image formation apparatus of the present invention;

FIG. 60 is a partial cross-sectional view of the display panel sectionof the image formation apparatus, another example of the presentinvention;

FIG. 61 is a partial cross-sectional view of the display panel sectionof the image formation apparatus, another example of the presentinvention;

FIG. 62 is a cross-sectional view showing an exemplar spacer used in thedisplay panel of the image formation apparatus of the present invention;

FIG. 63 a is a partially cut out perspective view of the display panelsection of the image formation apparatus, another example of the presentinvention;

FIG. 63 b is a schematic diagram showing an exemplar arrangement ofgetters and spacers;

FIG. 63 c is a C-C′ cross-sectional view of FIG. 63 b;

FIG. 64 a is a partially cut out perspective view of the display panelsection of the image formation apparatus, another example of the presentinvention;

FIG. 64 b is a schematic diagram showing an exemplar arrangement ofgetters and spacers;

FIG. 64 c is a C-C′ cross-sectional view of FIG. 64 a;

FIG. 65 a is a partially cut out perspective view of the display panelsection of the image formation apparatus, another example of the presentinvention;

FIG. 65 b is a schematic diagram showing an exemplar arrangement ofgetters and spacers;

FIG. 66 a is a partially cut out perspective view of the display panelsection of the image formation apparatus, another example of the presentinvention;

FIG. 66 b is a schematic diagram showing an exemplar arrangement ofgetters and spacers;

FIG. 66 c is a C-C′ cross-sectional view of FIG. 66 b;

FIG. 67 a is a partially cut out perspective view of the display panelsection of the image formation apparatus, another example of the presentinvention;

FIG. 67 b is a partial cross-sectional view of the display panel sectionshown in FIG. 67 a;

FIG. 68 is a plan view schematically showing a wired in matrixconfiguration of two-dimensionally placed electron beam sources appliedto the image formation apparatus of the present invention;

FIG. 69 is an A-A′ cross-sectional view of FIG. 68;

FIG. 70 a is a partially cut out perspective view of the display panelsection of the image formation apparatus, another example of the presentinvention;

FIG. 70 b is an enlarged plan view of the electron beam sources shown inFIG. 70 a;

FIG. 71 a is a partially cut out perspective view of the display panelsection of the image formation apparatus, another example of the presentinvention;

FIG. 71 b is an enlarged plan view of the electron beam sources shown inFIG. 70 a;

FIG. 72 a is a perspective view showing a exemplar structure of anintersection of a lower wire and an upper wire;

FIG. 72 b is a perspective view showing another exemplar structure of anintersection of a lower wire and an upper wire;

FIG. 73 a is a schematic view showing floating or distortion of a mask;

FIG. 73 b is a schematic view to explain diffraction of anon-evaporation type getter;

FIG. 74 is a partially cut out perspective view of the display panelsection of the image formation apparatus, another example of the presentinvention;

FIG. 75 is a partial plan view of electron beam sources;

FIG. 76 is a B-B′ cross-sectional view of FIG. 75;

FIG. 77 is a partial plan view of electron beam sources;

FIG. 78 a is a partially cut out perspective view of the display panelsection of the image formation apparatus, another example of the presentinvention;

FIG. 78 b is an enlarged plan view of the electron beam sources shown inFIG. 78 a;

FIG. 79 a is an A-A′ cross-sectional view of FIG. 78 b;

FIG. 79 b is a schematic view showing a trajectory of an electron beam;

FIG. 80 a is a partially enlarged plan view schematically showing awiring structure of an electron beam source used in the image formationapparatus of the present invention;

FIG. 80 b is an A-A′ cross-sectional view of FIG. 80 a;

FIG. 81 is a partially enlarged plan view of the electron beam sources;

FIGS. 82 a-82 f are manufacturing process diagrams to explain theprocedure for manufacturing the electron beam sources used in the imageformation apparatus of the present invention;

FIG. 83 is a partially enlarged plan view showing a exemplar structureof the wiring terminal section of electron beam sources used in theimage formation apparatus of the present invention;

FIG. 84 is a plan view schematically showing a configuration of anelectron beam source substrate of the electron beam sources used in theimage formation apparatus of the present invention;

FIG. 85 is a plan view showing part of the wired in matrix substrate ofthe electron beam sources used in the image formation apparatus of thepresent invention;

FIG. 86 is an A-A′ cross-sectional view of FIG. 85;

FIGS. 87 a-87 g are manufacturing process diagrams to explain amanufacturing procedure of the electron beam sources used in the imageformation apparatus of the present invention;

FIG. 88 is a configuration diagram schematically showing an outlinedconfiguration of a vacuum processing apparatus;

FIGS. 89 a-89 f are manufacturing process diagrams to explain amanufacturing procedure of the electron beam sources used in the imageformation apparatus of the present invention;

FIG. 90 is a partially enlarged plan view showing another exemplarstructure of the wiring terminal section of the electron beam sourcesused in the image formation apparatus of the present invention;

FIG. 91 is a partially enlarged plan view showing another exemplarstructure of the wiring terminal section of the electron beam sourcesused in the image formation apparatus of the present invention;

FIG. 92 is a partially enlarged plan view of the display panel sectionof the image formation apparatus, another example of the presentinvention;

FIG. 93 a is a partially enlarged view of the display panel section inFIG. 92;

FIG. 93 b is a partially enlarged view of FIG. 93 a;

FIG. 94 is a partially enlarged plan view showing part of the displaypanel section of the image formation apparatus, another example of thepresent invention;

FIG. 95 is an enlarged plan view showing another exemplar structure ofthe wiring terminal section of the electron beam sources used in theimage formation apparatus of the present invention;

FIG. 96 is an enlarged plan view showing another exemplar structure ofthe wiring terminal section of the electron beam sources used in theimage formation apparatus of the present invention;

FIG. 97 is a cross-sectional view of the image formation apparatushaving the wiring structure shown in FIG. 95 and FIG. 96;

FIG. 98 is an enlarged plan view showing another exemplar structure ofthe wiring terminal section of the electron beam sources used in theimage formation apparatus of the present invention;

FIG. 99 is an enlarged plan view showing another exemplar structure ofthe wiring terminal section of the electron beam sources used in theimage formation apparatus of the present invention;

FIG. 100 is an enlarged plan view showing another exemplar structure ofthe wiring terminal section of the electron beam sources used in theimage formation apparatus of the present invention;

FIG. 101 is an enlarged plan view showing another exemplar structure ofthe wiring terminal section of the electron beam sources used in theimage formation apparatus of the present invention;

FIGS. 102 a-102 d are manufacturing process diagrams to explain anothermanufacturing procedure of the electron beam sources used in the imageformation apparatus of the present invention;

FIG. 103 is a cross-sectional view showing a configuration of a metalbacking of the face plate used in the image formation apparatus of thepresent invention;

FIGS. 104 a-104 d are manufacturing process diagrams to explain amanufacturing procedure of the metal backing of the face plate used inthe image formation apparatus of the present invention;

FIGS. 105 a-105 e are manufacturing process diagrams to explain anothermanufacturing procedure of the metal backing of the face plate used inthe image formation apparatus of the present invention;

FIGS. 106 a-106 d are manufacturing process diagrams to explain anothermanufacturing procedure of the metal backing of the face plate used inthe image formation apparatus of the present invention;

FIGS. 107 a-107 b are enlarged plan views schematically showing anexemplar configuration of black matrix of the face plate used in theimage formation apparatus of the present invention;

FIGS. 108 a-108 d are manufacturing process diagrams to explain anothermanufacturing procedure of the metal backing of the face plate used inthe image formation apparatus of the present invention;

FIG. 109 a is a partially cut out perspective view of the display panelsection of the image formation apparatus, another example of the presentinvention;

FIG. 109 b is a partial cross-sectional view of the display panelsection shown in FIG. 109 a;

FIG. 110 a is a partially cut out perspective view of the display panelsection of the image formation apparatus, another example of the presentinvention;

FIG. 110 b is a partial cross-sectional view of the display panelsection shown in FIG. 110 a;

FIG. 111 is a partially cut out perspective view of the display panelsection of the image formation apparatus, another example of the presentinvention;

FIGS. 112 a-112 b are enlarged plan views schematically showing anotherexemplar configuration of black matrix of the face plate used in theimage formation apparatus of the present invention;

FIG. 113 is an enlarged plan view schematically showing an example ofarrangement pattern of fluorescent materials of the face plate used inthe image formation apparatus of the present invention;

FIG. 114 is a cross-sectional view showing a configuration of the faceplate of the display panel section of the image formation apparatus,another example of the present invention;

FIG. 115 is a partial cross-sectional view of the display panel sectionof the image formation apparatus, another example of the presentinvention;

FIG. 116 is a developed perspective view of the display panel section ofthe image formation apparatus, another example of the present invention;

FIG. 117 is a partial cross-sectional view of the anode terminal sectionviewed from the direction shown by arrow A in FIG. 116;

FIGS. 118 a-118 e are process diagrams schematically showing amanufacturing procedure of the rear plate substrate;

FIG. 119 is a plan view showing a peripheral part of the anode terminalsection of the rear plate;

FIG. 120 is a developed perspective view of the display panel section ofthe image formation apparatus, another example of the present invention;

FIGS. 121 a-121 c are schematic views showing an example of formation ofleading wires of the face plate;

FIG. 122 is a block diagram showing a configuration of a high voltagepower supply section that supplies a high voltage;

FIG. 123 a is an external view of the display panel with the componentsshown in FIG. 121 and FIG. 122 assembled into the apparatus;

FIG. 123 b is a cross-sectional view showing a configuration of thecabinet interior viewed from the direction shown by arrow A in FIG. 123a;

FIG. 123 c is a configuration diagram of the cabinet of the displaypanel in FIG. 123 a with the rear plate removed viewed from thedirection shown by arrow B;

FIG. 124 a is a plan view of the vacuum panel viewed from the face plateside;

FIG. 124 b is a cross-sectional structural view of a peripheral sectionof a high-voltage terminal structural section viewed from the A-A′direction in FIG. 124 a;

FIGS. 125 a-125 g are process diagrams showing a manufacturing procedureof a high-voltage power supply leading wire;

FIG. 126 a is a plan view of an electrode section;

FIG. 126 b is an F-F′ cross-sectional view of FIG. 126 a;

FIG. 127 is a schematic view showing trajectories of back-scatteringelectron beams;

FIG. 128 is a developed perspective view of the display panel section ofthe image formation apparatus, another example of the present invention;

FIG. 129 is a cross-sectional view of the image formation apparatusshown in FIG. 128 viewed from the Y-direction;

FIGS. 130 a-130 b are enlarged plan views schematically showing anotherexemplar configuration of black matrix of the face plate used in theimage formation apparatus of the present invention;

FIG. 131 is an enlarged cross-sectional view of the main section of theface plate used in the image formation apparatus of the presentinvention;

FIG. 132 is a front view of the image display apparatus, another exampleof the present invention;

FIG. 133 is a front view of the image display apparatus, another exampleof the present invention;

FIG. 134 a is a schematic view showing one side of the rear platematched with one side of the face plate;

FIG. 134 b is a schematic view showing two sides of the rear platematched with two sides of the face plate;

FIG. 135 is a front view of the image display apparatus, another exampleof the present invention;

FIG. 136 is a front view of the image display apparatus, another exampleof the present invention;

FIG. 137 is an enlarged perspective view schematically showing the mainsection of the display panel section of the image display apparatus,another example of the present invention;

FIG. 138 is a cross-sectional view of the part that connects a drive ICto the wiring terminal section;

FIG. 139 is a schematic view showing a layout of the extractionelectrode section;

FIG. 140 is a cross-sectional view showing an example of the electrodestructure of the electron beam sources used in the image displayapparatus of the present invention;

FIGS. 141 a-141 b are partially enlarged views showing an exemplarconfiguration of the wiring terminal section on the column side of partA shown in FIG. 139;

FIG. 142 is a schematic view showing a substrate layout of the electriccircuit substrate of the drive electrical circuit section used in theimage display apparatus of the present invention;

FIG. 143 is a functional block diagram of the drive electrical circuitsection used in the image display apparatus of the present invention;

FIG. 144 is a timing chart to explain the operation of the driveelectrical circuit section shown in FIG. 143;

FIG. 145 is a schematic view showing a layout of a connector on the rearplate side of the display panel used in the image display apparatus ofthe present invention;

FIG. 146 is a schematic view showing a layout example when the controlsection, drive section and power supply section, etc. are mounted on thedisplay panel shown in FIG. 145;

FIG. 147 is a schematic view showing another layout example when thecontrol section, drive section and power supply section, etc. aremounted on the display panel shown in FIG. 145;

FIG. 148 is a schematic view showing another layout example when thecontrol section, drive section and power supply section, etc. aremounted on the display panel shown in FIG. 145;

FIG. 149 is a block diagram showing an outlined configuration of thepart that performs processing to display images;

FIG. 150 is a perspective view showing a mounting structure of anacceleration voltage terminal and a positional relationship between arow wire, column wire and acceleration electrode;

FIG. 151 is a front view of the rear plate of the display panel;

FIG. 152 is a block diagram showing a configuration of another imagedisplay apparatus of the present invention;

FIG. 153 is a timing chart to explain a diselectrification driveoperation applied to the image display apparatus of the presentinvention;

FIG. 154 is a flow chart when diselectrification drive is performed bysequence processing;

FIG. 155 is a timing chart when diselectrification drive is performedwhile an image is being displayed;

FIG. 156 is flow chart when diselectrification drive is performed bysequence processing while an image is being displayed;

FIG. 157 is a timing chart showing drive timing of the image displaysection of the image display apparatus of this embodiment;

FIG. 158 is a perspective view of the display panel;

FIGS. 159 a-159 e are process diagrams showing a procedure formanufacturing multi-electron beam sources;

FIG. 160 is a block diagram showing an exemplar configuration of thedrive circuit that drives the display panel;

FIGS. 161 a-161 c are process diagrams showing a procedure formanufacturing multi-electron beam sources;

FIG. 162 a is a partially enlarged view of the image display panel usedin the image display apparatus of this embodiment;

FIG. 162 b is a partial cross-sectional view of the display panel shownin FIG. 162 a;

FIG. 163 illustrates an equivalent circuit of the multi-electron beamsources of the display panel;

FIG. 164 is a partial cut out perspective view of the display panelsection of the display panel section of the image formation apparatus,another example of the present invention;

FIG. 165 is a cross-sectional view of the display panel section of theimage formation apparatus, another example of the present invention;

FIG. 166 is a schematic view to explain temperature control of the faceplate and rear plate;

FIG. 167 is a cross-sectional view of the display panel section of theimage formation apparatus, another example of the present invention;

FIG. 168 is a cross-sectional view of the display panel section of theimage formation apparatus, another example of the present invention;

FIG. 169 is a block diagram of the panel drive circuit;

FIG. 170 is a flow chart showing a processing procedure for powering-on;

FIG. 171 is a flow chart showing a processing procedure forpowering-off;

FIG. 172 is a flow chart showing a processing procedure in the event ofan abnormality;

FIG. 173 is a characteristic diagram showing a drive voltage vs.electron emission quantity characteristic of an electron emissiondevice;

FIG. 174 is a block diagram showing an exemplar multi-function displayapparatus to which the configuration of the image formation apparatus ofthe present invention is applied;

FIG. 175 is a cross-sectional view showing a cross-sectional shape ofthe face plate;

FIG. 176 a is a plan view of the electrode section of the display panelused in the image formation apparatus of the present invention;

FIG. 176 b is an F-F′ cross-sectional view of FIG. 176 a;

FIG. 177 is an enlarged view of the electron beam source substratebefore electrification forming step; and

FIG. 178 is a block diagram showing an example of aninterlace-progressive conversion (IP conversion) circuit used in theimage formation apparatus of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An example of the image formation apparatus of the present invention isshown in FIG. 2. FIG. 2 is a developed assembly diagram of the imageformation apparatus and shows typical components. Reference numeral 1denotes a front cover made of metal or resin, etc. to protect theinterior of the product from dust, etc.; 2, a light-transmittable frontprotector made of resin or glass with low-reflection treatment, which isfixed to the inside of the front cover 1 by a fixing means duringassembly to protect the interior of the product from dust, etc.Reference numeral 3 denotes a top left plate; and 4, a top right plate,both of which are configured by metal plates, etc. having rigidity tosandwich and support an image display panel 7, which will be describedlater. Reference numeral 5 denotes a front left heat insulator; and 6, afront right heat insulator, both of which are made of foaming resin orrubber to provide heat insulative and cushioning effect for the part tosandwich and support the image display panel 7, which will be describedlater. Reference numeral 7 is the image display panel, a selflight-emitting type image display apparatus called “SED”, which is avacuum container made up of two glass sheets and a frame whoseperipheral section is provided with a plurality of flexible cables.Reference numeral 8 denotes a back left heat insulator; and 9, a backright heat insulator, which sandwich and support the image display panel7 from the backside. These heat insulators can be made of the samematerial as that for the aforementioned front right and left heatinsulators 5 and 6.

Reference numeral 10 denotes a bottom left plate; and 11, a bottom rightplate, which sandwich and support the image display panel 7 from thebackside. These bottom left plate 10 and bottom right plate 11 are madeof the same material as that for the top left plate 3 and top rightplate 4, and the bottom left plate 10 and the top left plate 3, and thebottom right plate 11 and the top right plate 4 are fixed to each otherby fixing means such as screws.

The top left plate 3, bottom left plate 10, top right plate 4, bottomright plate 11 and heat insulators 5, 6, 8 and 9 make up a supportsection.

Though details will be given later, the display panel is made up of aface plate (image formation substrate or fluorescent material substrate)having a light-emitting material such as fluorescent material and a rearplate (electron beam source substrate) having an electron beam sourceconfigured by a plurality of electron emission devices, both of whichare placed face to face. Since the rear plate requires an extractionsection such as wires, etc. to drive the electron beam source, the rearplate is bigger than the face plate. For this reason, it is desirablethat the support section only support the rear plate. For simplicity ofattachment/detachment of the support section, it is further desirablethat the support section support the area where the rear plate and theface plate do not overlap.

As described above, the rear plate is provided with the drive wireextraction section. Furthermore, the extraction section is provided witha flexible cable to connect a drive circuit. For this reason, it isdesirable that the above-described support section support not only therear plate but also the flexible cable.

Reference numeral 12 denotes a left stopper of the flexible cable andreference numeral 13 is a right stopper, both of which not only sandwichand support the image display panel 7 but also connect and fix the topleft plate 3 and the bottom left plate 10, and the top right plate 4 andthe bottom right plate 11. These stoppers 12 and 13 are made of amaterial with rigidity such as metal and are provided with cable guidesin a staggered arrangement to pass the flexible cable of the imagedisplay panel 7. Reference numeral 14 is an X-figured frame (X frame)and made of metal having predetermined rigidity such as aluminum. This Xframe is provided with a screw fixing section for the aforementionedfront cover 1, fixing sections for the bottom left plate 10 and bottomright plate 11, fixing sections for a stand unit 15 and board mountingplate 16, which will be described later.

Reference numeral 15 denotes a stand unit whose interior is made ofmetal with rigidity and weight and whose exterior is made of resin withgood appearance or a metallic thin plate and is screwed to the X frame14 for the purpose of supporting the entire image formation apparatus.Reference numeral 16 denotes a board mounting plate and is a resin ormetal thin plate provided with a plurality of printed circuit boardfixing sections and fixed to the aforementioned X frame 14 by fixingmeans such as screws. Reference numeral 17 denotes an electric mountingboard equipped with an electric circuit, etc. to display images on theimage display panel 7 and is made up of a power supply section, a signalinput section, a signal control section, a panel drive section, etc.each of which is made up of a printed circuit board with electronicdevices mounted thereupon and connected to each other via electriccables, etc. Reference numeral 18 denotes a fan unit to dissipate heatgenerated from the aforementioned image display panel 7 and electricmounting board 17 out of the cabinet, is made of a fan and a fixingmaterial, and fixed to the aforementioned X frame 14 by fixing meanssuch as screws. Reference numeral 19 denotes a back cover and is made ofa metal or resin thin plate having heat radiation openings and protectsthe interior of the product from foreign matters such as dust.

FIG. 3 shows a developed view of an example of the display panel sectionand FIG. 4 shows an assembled view. Reference numeral 501 denotes therear plate made up of a glass plate, etc.; 502, exhaust pipes to exhaustair inside the panel to a vacuum; 503, a high voltage terminal to applya high voltage to the image formation section; 5044, an external frame(frame material) to support the peripheral regions of the panel; 505, agetter to adsorb a gas in the panel; 506, a peripheral support thatsupports an atmospheric pressure between the external frame and theimage formation section; 507, a spacer to provide resistance against theatmospheric pressure applied to the interior of the image formationsection; 508, the face plate made of a glass plate; 509, the imageformation section made up of an extraction electrode, a black stripe(mask material made of a low-resistance material), a fluorescentmaterial and a metal backing (metal film); 510, an electron beam sourcesubstrate on which a plurality of electron emission devices are formed;511, Y-extraction wires to extract Y-direction wires from the electronbeam source area to the outside; 512, X-extraction wires to extractX-direction wires from the electron beam source area to the outside;513, sheet frits, which are temporarily baked frits in a sheet form tobond the exhaust pipes and high-voltage terminals; and 514, frits tobond the external frame with the rear plate and the face plate.

FIG. 5 is a plan view of the face plate 508 in FIG. 4 to explain thehigh-voltage terminal extraction section. FIG. 6 is an A-Across-sectional view of FIG. 4 and is a drawing to explain thehigh-voltage terminal section. Reference numeral 509 a denotes anextraction section formed on the face plate 508. Reference numeral 503 adenotes an insulator and 503 b denotes a lead-in wire made of aconductive material, and these make up the high-voltage terminal 503.The lead-in wire 503 b of this high-voltage terminal 503 is electricallyconnected to the extraction section 509 a formed on the face plate 508.

FIG. 7 is a B-B cross-sectional view of FIG. 4 to explain the getter andperipheral support. Reference numeral 505 a denotes a getter support;505 b, a support wire; 505 c, a getter material; 505 d, a getter frame;and 505 e, a getter loop, which make up the getter 505.

FIG. 8 schematically illustrates an example of a spacer layout providedon the display panel, FIG. 8 a is a top view of the display panel viewedfrom the face plate side and FIG. 8 b is a side view. In this example,multiple spacers are placed in parallel.

FIG. 9 schematically illustrates another example of a spacer layoutprovided on the display panel, FIG. 9 a is a top view of the displaypanel viewed from the face plate side and FIG. 9 b is a side view. Inthis example, spacers are placed in a staggered arrangement.

FIG. 10 shows an external frame provided with line getters andperipheral support 506 and FIG. 17 shows a configuration of the linegetter. This line getter 515 is set up as follows: First, a line gettermade of Ba, etc. is cut to a predetermined length to create a getterwire 515 and a Ni wire (frame wire 518), etc. is molded by folding, etc.in such a way that the Ni wire after folding becomes as long as thegetter wire in the non-evaporated direction and spot-welded atappropriate intervals, and in this way Ni wires and getter wires 515form a plurality of loops. This loop structure can be fixed by weldingthe loop structure to a metallic wire which is buried in a long, slendercolumnar glass support material and protruding from there. In theexample in FIG. 17, the line getter 515 is fixed to a GM support (rib)517 with a support wire 516.

FIG. 11 is a cross-sectional view of the display panel orthogonal to thelongitudinal direction of the spacer and reference numeral 4-1 denotes aface plate substrate; 4-2, a rear plate substrate; 4-3, row-directionwire (upper wire); 4-4, an electron emission section; 4-5, a conductivefrit; 4-6, a rear plate side spacer electrode; 4-7, a high-resistancefilm; 4-8, a spacer substrate; 4-9, a rear plate side spacer electrode;4-10, a black stripe; and 4-11, a green fluorescent material. Anelectron emitted from the electron emission section 4-4 is acceleratedby an acceleration voltage applied to a metal backing (not shown) formedon the face plate substrate 4-1 and collides with the fluorescentmaterial 4-11 placed just above the electron emission section 4-4,causing the fluorescent material to emit green light.

FIG. 12 is a cross-sectional view of the display panel in the directionparallel to the longitudinal direction of the spacer. Reference numeral5-1 denotes a face plate substrate; 5-2, a rear plate substrate; 5-3, acolumn-direction wire (lower wire); 5-4, a negative side deviceelectrode; 5-5, a positive side device electrode; and 5-6, a blackstripe. Reference numeral 5-7 denotes a blue fluorescent material; 4-8,a red fluorescent material; and 4-9, a green fluorescent material. Inthis cross-sectional direction, an electron emitted from the electronemission section (not shown) is accelerated by an acceleration voltageapplied to a metal backing (not shown) formed on the face platesubstrate 5-1 and collides with the color fluorescent materials 5-7 to5-9, causing the fluorescent materials to emit light. At this time,electrons are deflected toward the positive side device electrode 5-5,and therefore the fluorescent materials are placed at positions shifted(d) from the position right above the emission sections formed betweenthe device electrodes.

The spacer shown in FIG. 11 is provided with a spacer electrode outsidethe high-resistance film. As a configuration of this spacer surface, theconfiguration shown in FIG. 62 is also used favorably. The spacer 1320shown in FIG. 62 has low resistance films 1325 formed on the section(top end face) of the insulative base 1321 that contacts the face plateand the section (bottom end face) that contacts the rear plate and ahigh-resistance film 1322 is formed to cover the entire side of thebase.

FIGS. 13A to 13E and FIG. 14 show the process of formation of electronemission devices on the electron beam source substrate. Hereinafter, themethod of manufacturing this substrate with reference to these figureswill be explained.

First, an example of the method of manufacturing the electron emissionsubstrate panel of the present invention will be explained withreference to FIG. 13. First, a conductive film made of a metallicmaterial is formed on a well cleaned substrate 529 and the pattern issubjected to micro processing using photolithograph to form multiplepairs of device electrodes 521 and 522. Here, the substrate 529 can besilica glass, glass with reduced impurity content such as Na, soda limeglass, substrate with SiO₂ that is formed by a sputter method or CVDmethod, laminated on a soda lime glass, ceramics such as alumina, andthe like.

As the method of forming the device electrodes 521 and 522, it ispossible to select from among various methods such as forming a film bya vacuum-based method such as vacuum deposition method, sputteringmethod and plasma SVD method, then patterning by a lithography methodand etching or offset-printing MO paste containing organic metals usingglass recessed plate. The material for the device electrodes 521 and 522can be anything if it has conductivity, for example, metal or alloy suchas Ni, Cr, Au, Mo, W, Pt, Ti, Al, Cu, Pd or printing conductorconfigured by metal or metal oxide such as Pd, Ag, Au, RuO₂, Pd—Ag andglass, semiconductor material such as polysilicon, and transparentconductor such as In₂O₃—SnO₂ (FIG. 13 a).

Then, a conductive paste is formed by printing as the Y-direction wire524. At this time, the Y-direction wire 524 is formed in such a way asto connect to the device electrode 522. The wire with thick coating ismore advantageous because it is possible to reduce electricalresistance. For this reason, it is desirable to use a thick filmprinting method, especially screen printing method and it is possible touse conductive paste such as Ag, Au, Cu and Ni. In the case wherepatterning with higher resolution is required, a rough pattern is formedusing photo-sensitive paste by means of screen printing, then exposedand developed, and in this way it is possible to obtain optimal wires.After a desired pattern is formed, to eliminate a vehicle component inthe paste, the pattern is baked at a temperature (400 to 650° C.)according to a thermal characteristic of the paste and of the glasssubstrate used (FIG. 13 b).

Then, an inter-layer insulation film 525 is formed on the intersectionsbetween the X-direction wires and Y-direction wires. This inter-layerinsulation film is made of glass materials including, for example, leadoxide as a main component, such as mixture of components appropriatelyselected from among PbO, B₂O₃, ZnO, Al₂O₃, SiO₂, etc. The thickness ofthe inter-layer insulation film is not limited if insulativity can besecured at least. The thickness is normally 10 to 100 μm, preferably 20to 50 μm. This inter-layer insulation film is formed by applying pastemade up of a mixture of frit glass whose main component is lead oxide,appropriate polymers such as ethyl cellulose and organic solvents andvehicles to predetermined positions by means of screen printing and thenbaking (FIG. 13 c). Since the inter-layer insulation film only needs tobe applied to at least the intersections between the Y-direction wiresand X-direction wires, its shapes are not limited to those in FIG. 13.

Then, the X-direction wires 526 are formed on the inter-layer insulationfilm. Since it is also advantageous that the electrical resistance ofthese wires be reduced, it is desirable to use a thick film printingmethod capable of forming a thick film. Thus, as in the case of theformation of the Y-direction wires, wires are formed using conductivepaste according to a screen printing method and then baked. At thistime, each wire is connected to the device electrode 522 (FIG. 13 d).Then, a conductive thin film 523 is formed. Specific examples of thematerial thereof include metals such as Pt, Ru, Ag, Au, Ti, In, Cu, Cr,Fe, Zn, Sn, Ta, W and Pd, etc., oxides such as PdO, SnO₂, In₂O₃, PbO,Sb₂O₃, etc., borides such as HfB₂, ZrB₂, LaB₆, CeB₆, YB₄, GdB₄, etc.,carbides such as TiC, ZrC, HfC, TaC, SiC, WC, etc., nitrides such asTiN, ZrN, HfN, etc., semiconductors such as Si and Ge, etc., carbon,AgMg, NiCu, Pb, Sn, etc., which are made up of a fine particle film. Thefine particle film referred to here is a film made up of a congregate ofa plurality of fine particles and a film whose micro structure is notonly in a state in which fine particles are individually scattered butalso in a state in which fine particles are adjacent to each other oroverlapping one atop another (including island state).

A bubble-jet system is a means often used for forming thin films forformation of these electron emission sections. This is because thebubble-jet system has many advantages; the principle and configurationare very simple and it is easy to speed up the operation and reduce thesize of droplets, etc. In reality, a conductive thin film is formed withfine particles such as metals and metal oxides by giving a solution oforganic metal compounds including the aforementioned conductivematerials as droplets only at a predetermined position, drying and thenthermally decomposition the organic metal compounds through heattreatment (FIG. 14).

As the electron emission devices used for the present invention, it isdesirable to use those electron emission devices having a layer oflow-effective work function material, for example, a carbon layer, whichis a layer including carbon. This can be obtained by the activationprocess disclosed in the U.S. Pat. No. 5,591,061 and Japanese Patent No.2854532, etc. Especially, a carbon layer including graphite is ideallyused.

On the other hand, as the layer of low-effective work function material,the amorphic diamond film and CVD diamond film disclosed in the U.S.Pat. Nos. 5,679,043 and 5,763,997, etc. can also be used. These are alsoa kind of carbon layer.

FIG. 15 is a top view of the face plate viewed from the rear plate sideand FIG. 16 is an A-A′ cross-sectional view of FIG. 15. The face plateshown in these figures can be obtained, for example, as follows. First,a grid-like black matrix 62 is formed by screen printing on a substrate61 made of soda lime glass (blue-plate glass) with atmospheric pressureresistance or high distortion point glass with almost the samecoefficient of thermal expansion as that of a soda lime glass usingglass paste including inorganic black pigment. As the material for theblack matrix, a material having conductivity such as paste containingcarbon can also be used. Then, fluorescent material patterns of threeprimary colors of R, G and B (63-R, 63-G, 63-B) are formed on theopenings of the black matrix 62 using screen printing. Then, afterburning organic binders in the printing paste (e.g., at 430° C.),filming processing (process of forming an acryl-based thin film onfluorescent materials) normally used for CRTs, etc. is performed and analuminum thin film, for example, of 1000 Å to 2000 Å in thickness isformed by vapor deposition. Then, the glass substrate is baked at 430°C. to burn the acryl-based thin film between the aluminum thin film andfluorescent materials and a metal backing 64 made of an aluminum thinfilm of 1000 Å to 2000 Å in thickness is formed.

It is possible to use various configurations of the image display panelin the image formation apparatus above. For example, the one with theconfiguration shown in FIG. 18 can be used. This display panel isconfigured by placing a surface conduction type electron beam sourcesubstrate in a rear plate 4005 made of a glass material with atmosphericpressure resistance, a support frame (frame material) 4007 and a faceplate 4000, bonding predetermined joints of the components, and sealingthe space formed between the rear plate 4005 and the face plate 4000.Frit glass, etc. is used for this sealing. Inside the face plate 4000are a metal backing 4006 (details are not shown) and a fluorescentmaterial 4008 and a high-voltage terminal 4011 connected to the metalbacking 4009 is led out of the image formation apparatus and ahigh-voltage power supply 4010 is connected to this high-voltageterminal. Furthermore, column-direction wires 4003 and row-directionwires 4004 formed on the surface conduction type electron beam sourcesubstrate 4001 are connected to the X-direction terminal DX1, etc. andY-direction terminal DY1, etc., that extend toward outside the imageformation apparatus, respectively, and images are displayed on the faceplate by controlling emission of electrons from the electron emissiondevices 4002 using these wires according to image information. Here, ifthe electron beam source substrate has sufficient strength, the electronbeam source substrate can also have the function as the rear plate.

Hereinafter, examples with different configurations used in the presentinvention will be explained.

(First Configuration)

The interior of the display panel is sealed and shut out from theoutside so as to maintain a predetermined degree of vacuum as describedabove. It is general practice to further place getters in order tomaintain this internal degree of vacuum. Moreover, there are cases whereit is necessary to adopt various means and methods to secure sufficientresistance of the display panel itself against the atmospheric pressurewhen producing a vacuum inside. In such cases, spacers can be placedbetween the rear plate and face plate for the purpose of enhancingstructural strength, thus improving strength against the atmosphericpressure.

First, the relationship between this spacer and electrons emitted froman electron emission device will be explained using FIG. 26. In FIG. 26,reference numeral 30 denotes a face plate; 20, a spacer; 41, a spacerelectrode; 113, a wire; 111, an electron emission section; 31, a rearplate substrate on which an electron beam source is formed; 112, anelectron trajectory; and 25, an equipotential line. Electrons areattracted toward the spacer when the spacer 20 is charged. The spacerelectrode 41 is formed on the spacer 20 to adjust the potential close tothe electron emission section 111 near the spacer, and in this way it ispossible to lead the trajectory of electrons near the electron emissionsection in a direction repelling the spacer 20 to allow electrons toarrive at the normal position of the face plate 30.

Thus, as an example of placement of such a spacer and getter, thisconfiguration places the getter material on the wire electrode andavoids the support material from being placed on the getter. Suchexamples will be described below.

Example 1

An Example 1 of the First Configuration will be explained using FIG. 19.In FIG. 19, reference numeral 42 denotes a wire connected to the spacer;22, a high-resistance film formed so as to cover the entire side of thespacer base; 23, a spacer electrode made of a low-resistance film formedon the spacer on the section that contacts to the faceplate 30 (top endface); and 46, a joint. In FIG. 19, the face plate (fluorescent materialand metal backing, etc. are omitted in FIG. 19) 30, spacer 20, spacerelectrode 41 formed on the electron beam source substrate side, wire113, electron emission section 111, rear plate substrate 31 on which anelectron beam source is formed, electron trajectory 112, equipotentialline 25 and getter 101 have the same configurations as those shown inFIG. 26. To adjust the electron trajectory of electrons attracted by thecharged spacer 20, height “a” of the electrode 41 formed on the spaceris made larger than height “b” up to the top face of the getter. Thesize of “a” can be arbitrarily selected depending on height “b” up tothe top face of the getter, structure of the image formation apparatus,drive conditions, and antistatic capacity of the high-resistance film,but adjusting the electron trajectory against attraction of electronstoward the spacer 20 due to charging at least requires a>b. Furthermore,0≦a−b≦100 μm is desirable. However, in a situation in which charging ofthe spacer can be eliminated, it is possible to select a quasi-equalvalue for “a” and “b”. Moreover, it is also possible to select anarbitrary value for height “b” up to the top surface of the getter.Furthermore, it is possible to apply various manufacturing methods suchas sputter formation and thermal spray formation, etc.

This configuration avoids forming a getter at the location of thespacer, thus preventing the surface from being covered with the spacer,making it possible to increase the exposed area per a unit length andimprove the utilization rate of raw materials. Moreover, the spacerapplies no force to the getter 101, producing an effect that destructionor missing of the getter is not likely to occur in the spacer assemblyprocess or after evacuation. Furthermore, since the electron trajectoryis generally strongly affected by the electric field on the electronbeam source substrate side of the spacer, avoiding forming the getterbelow the spacer also has an effect of being able to apply a gettermanufacturing method that is hard to control height precisely.

This configuration makes it easier to form a getter film inside thedisplay area of the image formation apparatus without producingdisturbance of the electron trajectory near the spacer, making itpossible to provide a high-quality image formation apparatus with lesstime variation of brightness (reduction with time) and less beamdeviation.

Various methods can be applied to adjust the electron trajectory nearthe electron emission section. In addition to the above-described methodof increasing the height of the spacer electrode, it is also possible toincrease the height of the wires connected to the spacers. It ispossible to form all the wires by one operation using a high precisionformation method such as patterning using a photolithography method orscreen printing to the electron beam substrate. Using this method allowsthe deviation relative to the electron emission section to be reduced.

As the wire material, various conductive materials can be used. Forexample, in the case where wires are formed using a screen printingmethod, a material combining metal and glass paste can be used, while aplating bath material can be used in the case where metal isprecipitated using a plating method. With respect to the protuberantwiring section near the section that contacts the spacer, if the sectionwhose height is to be adjusted is electrically connected to the sectionformed below, it is possible to form the portion having the same heightas other wires by one operation using a method similar to that for otherwires and use a different manufacturing method only for the portionwhose height is to be adjusted. As the spacer shape, various shapes suchas a cylindrical shape can be used in addition to a tabular shape.

FIG. 20 is a perspective view of the display panel using this exampleand part of the panel is cut out to show the internal structure. In thefigure, components having the same configuration as that shown in FIG.18 are assigned the same reference numerals. In this example, too, therear plate 4005, side wall 4007 and face plate 4006 form an airtightcontainer to keep the interior of the display panel to a vacuum.

The configuration in FIG. 19 can be obtained, for example, as follows.After forming a column-direction wire (not shown) and insulation layer(not shown) on the electron beam source substrate 31, Ag paste isapplied using a screen printing method and the wire 113 (row-directionwire) is formed. Each wiring width is set to 300 μm. The thickness ofthe spacer 20 is set to 220 μm and the spacer electrode 41 is formed sothat the thickness becomes 0.2 μm.

The getter 101 used in this example is formed as follows. Getterformation is performed after wire formation. A non-evaporation typegetter film is formed on the row-direction wire 113 using a maskaccording to a reduced pressure plasma thermal spray method. The getterfilm is formed in an atmosphere of low-pressure argon and HS-405 (325mesh) powder, which is an alloy with a composition of Zr—V—Mn—Almanufactured by Japan Getters Incorporated is used as the gettermaterial. The film thickness of the getter material formed in thisexample is about 40μ on average. It is desirable that the getter 101formation area be equal to or slightly smaller than the width of thespacer. This is to prevent the getter from sticking out of the wire,causing the electron trajectory to deviate a great deal and it ispossible to select an arbitrary value.

In this example, the getter is formed with a length quasi-equal to thelength of the spacer, but it is also possible to form the getter in anarea without the spacer on the wires on which the spacer is placed. Thisis shown in FIG. 21. In FIG. 21, the same components as those in FIG. 18are assigned the same reference numerals. In this display panel example,the spacers 20 are placed at predetermined positions on the surfaceconduction type electron beam source substrate 4001 on whichrow-direction wires and column-direction wires are formed. No getter isformed beneath the spacers 20. This example is used when large-capacitygetters are required.

Example 2

A cross-sectional view of the panel of this example is shown in FIG. 22.In this example, the electrode 42 of the spacer 20 on the electron beamsource substrate side is only formed on the end face of the spacer andthe electron trajectory is adjusted by elevating the height of the wire42 on which the spacer is placed. The other configurations are the sameas those in Example 1.

Here, the method of forming the row-direction wire 42 will be explained.In this example, after forming a column-direction wire (not shown) andinsulation layer (not shown) on the electron beam source substrate 31,Ag paste is applied using a screen printing method and the row-directionwire 113 is formed. Furthermore, the row-direction wire 42 connected tothe spacer is formed in the same way as for other row-direction wire 113and then by printing multiple layers only on the wiring section with adifferent screen. In this example, after each row-direction wire 113 isformed with a thickness of 20 μm, the row-direction wire 42 is formed byapplying printing three times more. In this case, an amount of 25 μmadjusted in height is obtained. Moreover, the width of each wire is setto 300 μm. Moreover, the thickness of the spacer 20 is set to 250 μm andthe thickness of the spacer electrode 41 formed on the terminal sectionis set to 1 μm. The electrode is applied to the end face using adispenser and the spacer electrode 41 is formed by applying Ag paste ofapproximately 150 μm in width and baking it at 450° C.

In this example, the size of device pitch is set to 680 μm in the rowdirection and 300 μm in the column direction. “a” and “b” denote heightsincluding the column-direction wire and the thickness of the insulationlayer, and in this example, the size of “a” is 95 μm and the size of “b”is 65 μm supposing the thickness of the getter 101 is 35 μm.

Example 3

FIG. 23 shows an Example 3 of the First Configuration. The configurationof this example is the same as the configuration of the Example 1 exceptthat no high-resistance film is provided on the surface 22 of the spacer20. In this example, the size of device pitch is set to 800 μm in therow direction and 600 μm in the column direction. The heights of thespacer electrodes 41 and 23 are both set to 180 μm and the size of “a”is set to 230 μm and the size of “b” is 100 μm supposing the thicknessof the getter 101 is 50 μm.

Example 4

FIG. 24 shows an Example 4 of the First Configuration. The configurationof this example is the same as the configuration of the Example 1 exceptthat no high-resistance film and no spacer electrode on the face plateside is provided for the spacer 20. In this example, an insulative fritwithout conductive fillers is used for the joint section 46.Furthermore, in this example, the thickness of the getter formed on therow-direction wire 113 adjacent to the spacer is greater than otherwires. This configuration makes it possible to adjust the electrontrajectory of electrons emitted from the electron beam source adjacentto the spacer and the electron beam source adjacent thereto.

In this example, the size of device pitch is set to 800 μm in the rowdirection and 450 μm in the column direction. The height of the spacerelectrode 41 is set to 600 μm and the size of “a” is set to 650 μm andthe size of “b” is 150 μm supposing the thickness of the getter adjacentto the spacer is 100 μm and the size of “c” is set to 100 μm supposingthe thickness of other getters is 50 μm.

Example 5

FIG. 25 shows an Example 5. The configuration of this example is thesame as the configuration of the Example 1 except that columnar spacers102 are used. Though not shown in the figure, the spacers 102 areprovided with a spacer electrode and high-resistance film and thespacers are formed as follows:

With regard to the manufacturing method of the spacer electrode, Agpaste is spread to a uniform thickness on a flat plate using a barcoater. Then, the Ag paste, which is an electrode material, istransferred to the column side by pressing the end face of the columnarspacer onto this spread Ag paste. After drying this column at 120° C.,the column is turned upside down and the same Ag paste is transferredlikewise and after drying, electrodes are formed at the top and bottomof the column by baking for 2 hours at 450° C. Moreover, ahigh-resistance film is formed on the entire surface of the spacer 102by applying sputtering similar to that in the Example 1 twice. Othercomponents such as the getter 101 are formed using the same method asthat in the Example 1.

In this example, the size of device pitch is set to 550 μm in the rowdirection and 250 μm in the column direction. The heights of the spacerelectrodes (not shown) on the electron beam source substrate side and onthe face plate side are both set to 60 μm and the thickness of thegetter is set to 40 μm.

When the image formation apparatus has the above configuration in whichthe panel inner thickness d is 1.4 mm and acceleration voltage is 6 kV,this example can provide an extremely high-quality image with lesscharacteristic deterioration and no color shift.

The above-described First Configuration makes it possible to provide ahigh-quality image apparatus with less characteristic deterioration withno brightness variation, no color shift by placing getters within thescreen area and placing spacers where there is no getter. Furthermore,similar effects can be produced with an electron generation apparatusmaking up a multiple planar electron beam source without specifyingelectron beam irradiation targets.

(Second Configuration)

The above-described First Configuration can be further configured asfollows.

FIG. 27 is a perspective view of a display panel to which a SecondConfiguration of the present invention is applied and part of the panelis cut out to show the internal structure. FIG. 28 is a schematic viewof the A-A′ cross-section of FIG. 27. In FIG. 28, reference numeralsassigned to components are the same as those in FIG. 27. In the FIGS.,reference numeral 1015 denotes a rear plate; 1016, a side wall (supportframe); 1017, a face plate, and the rear plate 1015, side wall 1016 andface plate 1017 form an enclosure (sealed container) to keep theinterior of the display panel to a vacuum. Furthermore, the interior ofthe sealed container is provided with spacers 1020 to support anatmospheric pressure.

A fluorescent material film 1018 and metal backing 1019 are formed onthe face plate 1017. A substrate 1011 is fixed to the rear plate 1015and N×M cold cathode devices 1012, which are wired with M row-direction(X-direction) wires 1013 and N column-direction (Y-direction) wires1014, are formed on this substrate 1011.

Reference numeral 1021 denotes a non-evaporation type getter formed onthe row-direction wire 1013 on which the spacer 1020 is placed; 1022, anadhesive that bonds the face plate 1017 and the spacer 1020 via themetal backing; 1101, an electron trajectory of electrons emitted fromthe electron emission device 1012 near the spacer; and 1102,equipotential lines near the spacer.

The spacer 1020 is made up of a thin-plate insulative material 1201coated with high-resistance film 1211, and the side of the spacercontacting the inner side (metal backing 1019) of the face plate 1017and the side 1203 of the spacer contacting the surface of the substrate1011 (row-direction wire 1013) are coated with a low-resistance film1221. The thin-plate spacer 1020 is placed in row direction(X-direction). The high-resistance film 1211 is electrically connectedto the row-direction wire 1013 via the low-resistance film 1221 andnon-evaporation type getter 1021 on the substrate 1011 side, andelectrically connected to the metal backing 1019 via the low-resistancefilm 1221 and adhesive 1022 on the face plate 1017 side.

It is desirable that at least 5 to 50 row-direction wires be placedbetween the row-direction wires on which the above-described spacers areplaced.

The non-evaporation type getter 1021 and adhesive 1022 have a cushioningfunction between the wire 1013, metal backing 1019 and spacer 1020 whenthe spacer 1020 has a mechanical and electrical contact with the wire1013 or metal backing 1019.

This configuration provides an effect of preventing the extremely thinmetal backing 1019 from peeling or being torn, an effect of preventingthe resistance of the wire 1013, which is required to have smallspecific resistance, from increasing due to cracks or an effect ofpreventing the spacer made of a brittle material from being damaged,etc.

The non-evaporation type getter 1021 and adhesive 1022 can have theabove-described cushioning effect for both the face plate 1017 side andthe substrate 1011 side that makes up the electron beam source.

Furthermore, the above cushioning effect is naturally effective in anarea other than the image display area (e.g., the wire extractionsection).

Moreover, from the standpoint of control of the electron trajectory nearthe spacer, in order to adjust the trajectory of electrons attracted bythe positively charged spacer 1020, height “a” of the electrode 1221formed on the spacer 1020 is set to be greater than height “b” up to thetop surface of the getter (up to the top surface of the wire if there isno getter). The size of “a” can be arbitrary selected depending onheight “b” up to the top surface of the getter, the structure of theimage formation apparatus, drive conditions, antistatic capacity of thehigh-resistance film, but adjusting the electron trajectory againstelectrons being attracted to the charged spacer 1020 requires at leasta>b. However, under a circumstance under which it is possible toeliminate charging of the spacer, a quasi-equal value can be selectedfor “a” and “b”. It is also possible to select an arbitrary value forheight “b” up to the top surface of the getter.

Here, it is desirable that the height of the top end of the electrode1221 formed for the spacer 1020 exceed the top surface of the electronemission section of the electron emission device. On the other hand,supposing the potential distribution between the potential of theelectron emission device when electrons are emitted from the electronemission device and the potential at the acceleration electrode isuniform, it is preferable to control the upper limit of the height ofthe electrode to such a height that the potential on the accelerationelectrode side becomes by 2 kV higher than the potential at the electronemission section. Here, the potential of the electron emission sectionwhen electrons are emitted refers to a higher one of the potentialsapplied to the electron emission section. The electrode 1221 formed onthe spacer is not limited to the one that wraps the side of the spaceras shown in FIG. 28, but can also be one that is formed only on the endface that contacts the wire. In this case, the height of the top end ofthe electrode formed on the spacer above refers to the height of thecontacting surface between the electrode and the base formed on thespacer. After such an electrode (resistance film) is formed on thespacer, the above condition is also ideally applicable to a case where ahigh-resistance film with higher sheet resistance than the electrode isformed.

This configuration makes it easier to form a getter film in the displayarea of the image formation apparatus without producing disturbance ofthe electron trajectory near the spacer, providing a high-quality imageformation apparatus with less time variation of brightness (reductionwith time) and less beam shift. Moreover, the spacer is available invarious forms in addition to a tabular form, such as a columnar form.Glass is suitable as the material of the spacer. An appropriate heightof the spacer is 0.5 mm to 5 mm.

As shown in FIG. 28, there is a case where an auxiliary getter 1023 isplaced in the enclosure as an auxiliary pump to keep the interior of theenclosure to a vacuum. In this case, it is possible to provide a shield1024 between the auxiliary getter 1023 and the area including theelectron emission device 1012, wires 1013 and 1014 and the metal backing1019 with a film thickness of 500 Å to 5000 Å constituting anodeelectrode (using a metal film such as aluminum, copper and silver) forthe purpose of preventing the getter material from scattering into theimage display area, causing electrical short-circuit between theelectrodes. If the getter 1021 formed in the image display area alonecan sufficiently keep the interior of the enclosure to a vacuum, theauxiliary getter 1023 and shield 1024 need not be formed. The filmthickness of the metal backing 1019 is thin enough to allow electrons topenetrate.

Example 1

Here, details of the getter and spacer, which are the most distinctivecharacteristics of the present invention, will be given. FIG. 29 andFIG. 30 are drawings to explain examples of the Second Configurationdescribed above and are the cross-sectional views of the display panelmaking up the electron beam apparatus. The low-resistance film 1221 ofthe spacer 1020 is created with aluminum to a thickness of approximately0.1 μm using a mask jig according to a sputtering method and formed onthe face plate 1017 side and electron beam source substrate 1011 side.The low-resistance film 1221 on the electron beam substrate 1011 side isonly formed on the surface 1203 that contacts the electron beamsubstrate 1011. Then, as the high-resistance film 1211, a film made ofW—Ge alloy nitride is formed to a thickness of approximately 0.2 μmaccording to an reactive sputtering method by which a W target and Getarget are sputtered simultaneously in a Ar—N₂ mixed gas. At this time,the sheet resistance of the high-resistance film 1211 is approximatelythe tenth power of 10 [Ω/□]. A study by the authors, et al. confirmsthat the film of W—Ge alloy nitride with conductivity has an excellentantistatic characteristic.

In this example, the non-evaporation type getters 1021 (200 μm wide, 40μm thick) are formed having the quasi-same length as that of therow-direction wire on all the row-direction wires 1013.

Furthermore, after the column-direction wires (not shown) and insulationlayers (not shown) are formed on the electron beam source substrate1011, Ag paste is applied according to a screen printing method androw-direction wires 1013 (20 μm thick) are formed in this example. Eachwire is formed to a width of 300 μm. The row-direction pitch of theelectron emission device 1012 is set to 630 μm and the column-directionpitch is set to 305 μm.

In this example, the spacer 1020 is placed by assembling the electronbeam source substrate 1011 and the face plate 1017 after fixing thespacer 1020 to the face plate 1017 with the adhesive 1022. As theadhesive 1022, a spherical glass insulative filler with metal platingapplied then scattered into frit glass is used to electrically connectthe face plate 1017 and low-resistance film 1221 on the face plate sideand to fix the spacer 1020.

Example 2

This example adopts a configuration shown in FIG. 14 with therow-direction wires in Example 1 made wider than the column-directionwires. In addition a spacer is placed on the row-direction wires.

Scanning signals are input to the row-direction wires to display images.For this reason, this example uses row-direction wires wider thancolumn-direction wires to reduce the resistance of the row-directionwires. Moreover, it is possible to reduce the precision required foralignment of the spacer compared with Example 1.

As a configuration of fluorescent material films of the face plate ofthe image formation apparatus formed, this example uses the one shown inFIG. 15. As shown in the figure, each color fluorescent material has anoblong rectangular shape. As an arrangement of three primary colors,fluorescent materials of the same color are placed in the columndirection (Y direction in the figure) and fluorescent materials of threeprimary colors are placed repeatedly in the row direction (X direction)in order of R, G and B. A black matrix is used as the light shieldmaterial and the pitch between adjacent fluorescent materials of thesame color (Y direction in the figure) is made wider than the pitchbetween adjacent fluorescent materials of different colors (X directionin the figure) and the same arrangement on the rear plate side is used.That is, the row-direction wires are placed right below the area of thewider light shield materials. Spacers are placed in contact with thearea of the wider light shield materials. The rest of the structure isthe same as that in the Example 1 of the Second Configuration.

The configuration above can implement an image formation apparatus witha greater area and higher brightness in this example.

(Third Configuration)

The following configuration can be used to fix spacers.

(In the Case of Fixing Spacers to Rear Plate)

On the rear plate, matrix or ladder figured wires are formed to drivedevices on the rear plate. When spacers are fixed to the rear plate, thespacers are fixed onto the wires using frit glass, etc. At this time,contact between the spacers and face plate is made via a black stripe.

(In the Case of Fixing Spacers to Face Plate)

When spacers are fixed to the face plate, the spacers are fixed to theblack stripe using frit glass, etc. as in the case of the rear plate.Contact between the spacers and rear plate is made via a wire.

(Cross Section of Wire and Black Stripe)

Wires and black stripes are formed using techniques such as printing andphotolithography and have a cross section of a fan, semicylindrical orrectangular shape and have contact with spacers at vertices, on a lineor plane.

(Allowable Range of Spacer Deviation)

In the case where wires and black stripes have a convex cross section,the spacers are connected to the rear plate or face plate or both viawires and black stripes as described above, but there can be discrepancyin positions between the wires and black stripes on which the spacersare placed and the spacers. As a result, the corner of a spacer maytouch the stand depending on the amount of deviation of the spacer, andtherefore the allowable range of deviation is set as shown in FIG. 31.

Suppose a deviation between a normal 1235 drawn from a vertex of thestand 1231 placed on the rear plate 1230 (or face plate) (here, acontact 1233 between the spacer 1020 and stand 1231) and the spacercenter axis 1234 is x and the thickness of the spacer 1020 is t, andx<t/2

(Allowable Range of Spacer Inclination)

What matters with the spacer 1020 is not only deviation but alsoinclination. Certain inclination of the spacer 1020 with respect to thestand 1231 can overload and damage the corners. For this reason, theinclination is limited to within the following allowable range as shownin FIG. 32.

Suppose the thickness of the spacer 1020 is t, radius of curvature ofthe stand 1231 with a curvature center 1236 is R and the inclination ofthe spacer 1020 is θ, then,R sin θ<t/2

(Allowable Range of Spacer Deviation and Inclination)

Moreover, there is a case where both deviation and inclination occur. Insuch a case, it is desirable to limit the inclination to within thefollowing allowable range as shown in FIG. 33.

Suppose the thickness of the spacer 1020 is t, radius of curvature ofthe stand 1231 with a curvature center 1236 is R and the inclination ofthe spacer 1020 is θ, and the direction of inclination of the spacer1020 with respect to the plane of the face plate 1017 (or rear plate) isthe X-axis and deviation of the spacer 1020 on the stand 1231 is x. Whena contact 1233 between the spacer 1020 and the stand 1231 is greateralong the X-axis direction than the center of thickness of the spacer1020, ifR sin|θ|<x+t/2then, the spacer corner does not contact the stand.

Suppose the thickness of the spacer 1020 is t, radius of curvature ofthe stand 1231 is R and the inclination of the spacer 1020 is θ, and thedirection of inclination of the spacer 1020 with respect to the plane ofthe rear plate 1230 is the X-axis and deviation of the spacer 1020 onthe stand 1231 is x. When the contact 1233 between the spacer 1020 andthe stand 1231 is between the center of thickness of the spacer and avertex of the stand 1231, ifR sin|θ|>x−t/2then, it is possible to avoid the spacer corner from touching the stand(see FIG. 34).

(Providing R for Spacer)

In addition to suppressing deviation and inclination of the spacer 1020,it is also possible to round the corner of the spacer 1020 and reduceconcentration of load. It is desirable that R of the corner of thespacer 1020 be at least 10 μm and it is desirable to use appropriate Raccording to the strength of the spacer 1020, width and curvature of thewires and the black stripe, etc.

(Stand Having Flat Area Wider than Spacer)

In the case of the stand 1231 with the flat area that contacts thespacer 1020 having a wider surface than the spacer 1020, suppose thethickness of the spacer 1020 when the spacer 1020 is placedperpendicular to the stand is t, deviation of the spacer 1020 is x andwidth of the flat area of the stand 1231 is w. If the center of thespacer 1020 is deviated from the stand 1231, it is possible to suppressinterference between the corner of the spacer 1020 and the stand 1231under the following condition (see FIG. 36).x<w/2+t/2

It is possible to suppress damage of the spacer due to an atmosphericpressure by satisfying the above-described conditions.

Examples of the above-described Third Configuration will be shown below.

Example 1 Setting Tolerance of Tilt and Positional Deviation

In this example, the above mentioned display panel shown in FIG. 27 wasproduced.

(1) Producing Electron Source

First, the row direction wiring 1013, the column direction wiring 1014,the inter-electrode insulating layer, the device electrode of thesurface conductive electron emission device 1012, and the conductivefilm were formed on the substrate 1011 (refer to FIG. 27).

(2) Producing Spacer Substrate

Then, a spacer 1 (40 mm×2 mm×0.2 mm) made of an insulating material ofsoda-lime glass was produced.

(3) Forming High Resistance Film and Electrode Film of Spacer

In the four areas (the top and reverse sides of each of the 40×2 and40×0.2 areas) in the image area of the air-tight container on thesurface of the spacer was formed a high resistance film 1211 describedlater, and a conductive film was formed on the two areas (both sides of40×0.2) touching the face plate and the rear plate, and on the area(40×0.1) at the height of up to 0.1 mm from the side touching the faceplate and the rear plate of the 40×2 areas. As a high resistance film, aCr—Al alloy nitride film (200 nm thick, approximately 1×10⁹ [Ω/□])formed by simultaneously spattering the Cr and Al targets using highfrequency power supply was used. The conductive film was used to ensurethe electric connection between a high resistance film formed by aspacer and a face plate, and between a high resistance film and a rearplate, and was also used to control the electric field around the spacerand to control the orbit of the electron beam from the electron emissiondevice.

(4) Assembly of Face Plate and Spacer

The process of assembling a face plate and a spacer will be describedbelow by referring to FIG. 37. A frit 1022 a was applied to the portionwhere the spacer 1020 was to be placed on the face plate 1017. Then, atthe place where the spacer 1020 was to be placed, a jig 1022 c having agroove 1022 b a little larger than the spacer was aligned with the faceplate 1017. Then, the spacer 1020 was inserted in the groove 1022 b ofthe jig 1022 c, and a heating process was performed to fix the spacer1020 by the frit 1022 a. The groove of the jig used here was set to 250μm wide in consideration of the width of the spacer, the thickness ofthe film on the surface of the spacer, etc.

(5) Face Plate and Rear Plate Sealing

Next, the face plate 1017 to which the spacer was fixed was fixed to therear plate 1015. The frit glass was applied to the joint portion betweenthe rear plate 1015 and the side panel 1016, and the joint portionbetween the face plate 1017 and the side panel 1016. Then, the rearplate 1015 was applied to the face plate 1017 through the side panel1016, and sealed thereto by baking them at the temperature of 400° C. to500° C. in the atmospheric pressure for 10 minutes or more.

(6) Relationship Between Fixed Rear Plate and Spacer

In this present embodiment, as shown in FIG. 38, the spacer 1020 is 0.2mm thick and 2 mm high, the groove 1022 b of the jig is 0.25 mm wide,the wiring of the rear plate 1015 is 0.3 mm wide, and the curvature ofthe wiring is R=0.5 mm. Therefore, the maximum deviation of the spacer1020 is 0.025 mm, and the maximum tilt is 0.025 rad. Since the tilt is 0with the maximum deviation, x<t/2 is satisfied. With the maximum tilt, Rsin|θ|<x+t/2 is satisfied on the condition that the contact portionbetween the spacer and the setting stand is larger in the x axisdirection than at the center of the thickness of the spacer. Therefore,the corner of the spacer does not touch the wiring.

(7) Electron Source Process and Sealing

The airtight container completed as described above was exhausted by avacuum pump through an exhaust pipe, and after a sufficient vacuum levelwas reached, power was supplied to each device through the row directionwiring electrode 1013 and the column direction wiring electrode 1014 viaexternal container terminals Dx1 to Dxm and Dy1 to Dyn, to perform theabove mentioned electrification forming and activating processes,thereby producing a multi-electron beam source. Then, at the vacuumlevel of approximately 1×10⁻⁶ [Torr], the exhaust pipe not shown in theattached drawings was fused by heating it by a gas burner, thereby toseal the housing (airtight container). Finally, to maintain the vacuumafter the sealing, a getter process was performed.

(8) Image Forming

In the display panel completed as described above, an electron wasemitted by applying a scan signal and a modulation signal by the signalgeneration means not shown in the attached drawings to each of the coldcathode devices (surface conductive electron emission devices) 1012through the external container terminals Dx1 to Dxm and Dy1 to Dyn, andhigh voltage was applied to the metal backing 1019 through the highvoltage terminal Hv, thereby accelerating the emission electron beam sothat, an electron bombard against the fluorescent film 1018, and afluorescent material of each color was excited and emitted light. Thus,an image was displayed. The voltage Va applied to the high voltageterminal Hv was 3 [kV] to 10 [kV], and the voltage Vf applied to each ofthe wirings 1013 and 1014 was 14 [V].

At this time, emission spots in a string were arranged at equalintervals in a two-dimensional array including an emission spot by anelectron emitted from the cold cathode device 1012 near the spacer 1020,thereby displaying a clear and easily reproducible color image.

As described above, the maximum values of the position deviation and thetilt of the spacer on wiring were set, and the assembling process wasperformed in the set range, thereby avoiding the damage of the spacer bythe atmospheric pressure without the corner of the spacer touching otherportions.

Example 2 Wiring Having an Area Wider than Spacer

As shown in FIG. 39, the arrangement of a spacer on the wiring having anarea wider than the spacer will be described according to this example.The conditions of the spacer and the assembling process are the same asthose of the first example of the third configuration described above.That is, in this example, the spacer 1020 is 0.2 mm thick and 2 mm high,the groove of the jig is 0.5 mm wide, and the wiring of the rear plateis 0.3 mm wide, the plane of the wiring is W=0.2 mm wide (allowance ofthe deviation of the spacer). The conditions satisfy x<W/2+t/2.Therefore, the damage of the spacer by the atmospheric pressure can beavoided without the corner of the spacer touching other portions.

As described above, since the display panel to which the conditionsbased on the present invention were applied did not damage the spacer,the strength of the structure could be prevented from being lowered,thereby successfully maintaining the vacuum level. As a result, ahigh-quality image could be displayed with high luminous intensity.

(Fourth Configuration)

The inside of the display panel can also be configured as follows.

This configuration can also be basically designed as described above byreferring to FIG. 27. The electron beam emitted from the surfaceconductive electron emission device in the configuration of the insideof the display panel of the image display device to which the presentconfiguration is applied takes the orbit as shown above in FIG. 23. FIG.40 a is a schematic sectional view of a type of cathode substrate andanode substrate. FIG. 40 b shows a type of the shape of an electron beamon the anode substrate of the electron beam emitted from the surfaceconductive electron emission device. FIG. 40 c shows the distribution ofthe intensity along A-A′ shown in FIG. 40 b.

Each electron emission device is arranged in a matrix in the rowdirection and the column direction at intervals of Px and Py, and thevoltage application direction is parallel to the row direction. In theexample shown in FIG. 40, Vf is applied with the electrode 1102 set as ahigh potential side. The beam radii Sx and Sy on the anode substrate ofthe electron beam emitted from the electron emission device (devicelength: L) satisfy the following relation equations (I) and (II).Sx=Kx×2d(Vf/Va)^(1/2) [Kx: 0.8≦Kx≦1.0]  (I)Sy=L+2Ky×2d(Vf/Va)^(1/2) [Ky: 0.8≦Ky≦0.9]  (II)

where the distribution of the strength of the electron beam is biasedtoward the high potential side in the voltage application direction asshown in FIGS. 40B and 40C, and the shape of the beam is oval havinghigher intensity at a farther portion from the electron emission unit.Therefore, to maximize the amount of emission of an electron beam to afluorescent object with high uniformity, the positional relationshipbetween the source of an electron and the corresponding fluorescentobject can be optimized by setting the electron emission unit at adistance of Sx from the farther end of the corresponding fluorescentobject from the electron emission unit. Thus, although a part of theemitted electron is rejected by a black stripe 1010, the amount ofelectron for the fluorescent object can be maximized. As a result, highintensity can be obtained, the fluctuation from positional deviation canbe lower, and the uniformity can be enhanced.

A cylindrical spacer is mounted on the black stripe by setting thepositional relationship between the source of an electron and acorresponding fluorescent object as described above. With theconfiguration, the cylindrical spacer does not interferes the emissionof light. Therefore, a high quality image can be displayed.

(Position and Shape pf a Cylindrical Spacer)

The position of a cylindrical spacer is described below by referring toFIG. 41. FIG. 41 a is a top view of an anode substrate. FIG. 41 b is aside view of the inside of the image forming device. FIG. 41 c is a topview (vacuum side) of a cathode substrate. In this example, the spacer1020 is a cylindrical spacer, and is arranged at a non-emission positionof a primary electron beam emitted from the electron emission unit.Practically, the electron beam emitted from the electron emission unitreaches an anode substrate while being biased toward a high potentialside in the voltage application direction and gradually spreading in thevacuum. Therefore, the cylindrical spacer is not directly exposed to theprimary electron beam if it is arranged at a position where no electronbeams are emitted on the anode substrate. Therefore, the influence ofthe electron beam on the cylindrical spacer can be minimized. With theconfiguration, the spacer does not affect a displayed image, therebyrealizing a high quality image. The non-emission position of a primaryelectron beam emitted from the electron emission device is located at asubstantially central position between electron emission devicesadjacent to each other in the Y direction. Especially when the positionis at an equal distance from the devices, it is a desired position inrealizing high precision.

If the position is on the line of two electron emission devices adjacentin the Y direction, the cylindrical spacer is located between twoelectron beams emitted from the electron emission devices adjacent inthe x direction. Therefore, the spacer can be mounted withoutinterfering any electron beam although it is encompassed by fourelectron beams. With the configuration, the influences of charging byelectron beams can be minimized, thereby improving the yield of thespacer. Furthermore, the equalization in intensity among pictureelements can be improved, and a high quality image can be displayed.

There is a black stripe 1010 on the anode substrate immediately abovethe electron emission unit 1105, and the cylindrical spacer 1020 ismounted on the anode substrate and the black stripe 1010. Thus, thecylindrical spacer 1020 is connected to the anode substrate through theblack stripe 1010, and to the cathode substrate through an X directionwiring. The connection is not viewed from outside, but firmly fixed.Furthermore, the a small electric current flowing through the antistatichigh resistance film can be discharged when it is formed on the surfaceof the spacer. As a result, the cylindrical spacer does not affect animage, thereby providing a high quality image.

FIG. 42 shows a case in which the interval Py of the electron emissiondevices adjacent in the Y direction is larger than the Y direction beamradius Sy of the electron beam on the anode substrate. FIG. 42 a is atop view of the cathode substrate, and shows a multi-electron source.FIG. 42 b shows a type of the appearance of the visible light when theelectron beam emitted from the multi-electron source shown in FIG. 41 abombard the anode substrate. As shown in these drawings, when anelectron beam is contained in a pixel in the vertical direction, andthere is an area not accessible by an electron beam in the verticaldirection, the cylindrical spacer 1020 is mounted in the area of (Py−Sy)wide. In this case, it is desired that the contact area with thecylindrical spacer 1020 exists on the same line as the electron emissiondevice adjacent in the Y direction.

FIG. 43 shows another example of a trajectory area of an electron. FIG.43 shows a type of the appearance of a visible light when the electronbeam emitted from the multi-electron source bombard the anode substratewhen the interval Py of the electron emission devices adjacent to eachother in the Y direction is equal to or smaller than the radius Sy ofthe beam in the Y direction on the anode substrate of the electron beam.In this case, the electron beams from the electron emission devicesadjacent in the Y direction overlap each other on the fluorescentobject, it is desired that the shape of the spacer is cylindrical. Whenthe electron beams are on the same line as the electron emission devicesadjacent in the Y direction, the electron beams can be protected frombeing interfered by locating the cylindrical spacer exactly between theelectron beams emitted from the electron emission devices adjacent inthe X direction. As a result, a high-quality image can be displayed.

(Spacer Coated Layer: Common)

In the structure near the cylindrical spacer with the configurationshown in FIG. 40, the spacer 1020 has the high resistance film 1211 asantistatic means formed on the surface of the insulating material 1201,and has the low resistance film 1221 formed such that electricconnections can be made to the inside (metal backing 1019, etc.) of theface plate 1017, and to the surface (the row direction wiring 1013 orthe column direction wiring 1014) of the substrate 1101. A necessarynumber of the spacers 1020 are mounted and at necessary intervals toattain the above mentioned purpose, and are fixed inside the face plateand on the surface of the substrate 1101 with an adhesive material 1041.The high resistance film 1211 is formed at least on the area exposed inthe vacuum in an airtight container on the surface of the insulatingmaterial 1201, and is electrically connected to the inside (metalbacking 1019, etc.) of the face plate 1017 and to the surface (rowdirection wiring 1013 or column direction wiring 1014) of the substrate1101 through the low resistance film 1221 and the adhesive material 1041on the cylindrical spacer 1020. According to the aspect described below,the cylindrical spacer 1020 is electrically connected to the rowdirection wiring 1013.

It is necessary that the spacer 1020 is an insulator to stand the highvoltage applied between the row direction wiring 1013 and the columndirection wiring 1014 on the substrate 1101 and the metal backing 1019inside the face plate 1017, and a conductor to keep the surface of thespacer 1020 antistatic.

The insulating material 1201 of the spacer 1020 can be quartz glass,glass with a smaller content of impurities such as Na, etc., soda-limeglass, a ceramic material, etc. such as alumina, etc. The shape of thesection of the spacer 1020 can be set a polygonal, circular etc, suchthat the length (distance in the support direction between the cathodesubstrate and the anode substrate) of cylinders is sufficiently largerthan the length of the diagonal line of the shape. It is desired thatthe ratio (aspect ratio) of the length of the diagonal line of thesectional shape and the length of the spacer 1020 is 1:10 to 1:1000. Forexample, a spacer of 1 mm long and 100 μm×50 μm of rectangular sectionalshape, a spacer of 2 mm long and 100 μm in diameter of cylinder, etc.are appropriate.

The sectional shape of the spacer 1020 can be polygonal such as square,rectangular, diamond, hexagonal, circular, etc. as shown in FIG. 44 a toguarantee sufficient intensity, and have an area to mount the cathodesubstrate and the anode substrate on.

It is desired that the sectional shape is formed by curves such aspolygonal cylinders without corners as shown in FIG. 44 b, or cylindershaving circular and oval cross-sections without portions forconcentrating electric fields as shown in FIG. 44 c. Especially, since around cross-sectional cylinder is symmetric, it can be easily producedwith a larger allowance range for the connection direction andpositional deviation when it is mounted.

The electric current obtained by dividing the accelerating voltage Va tobe applied to the face plate 1017 (metal backing 1019, etc.) on the highpotential side by the resistance value Rs of the high resistance film1211 which is an antistatic film flows through the high resistance film1211 forming the spacer 1020. The resistance value Rs of the spacer 1020is to be set in a desired range in consideration of antistaticproperties and power consumption. From the viewpoint of the antistaticproperties, the surface resistance [R/□] is desired to be equal to orsmaller than 10¹²Ω. To obtain a sufficient antistatic effect, the valueis furthermore desired to be equal to or smaller than 10¹¹Ω. Since thelower limit of the surface resistance depends on the space shape and thevoltage applied between the spacers, it is desired to be equal to largerthan 10⁵Ω. The desired thickness t of the antistatic film formed on theinsulating material is in the range of 10 nm to 1 μm. Especially, italso depends on the surface energy of the material, the contact to thesubstrate, and the substrate temperature, but it is desired that thethickness of the film is 50 to 500 nm from the viewpoint of the filmgenerating time, reproducibility, the stress of the film. Consideringthe surface resistance [R/□]ρ/t, and the desired range of the abovementioned [R/□] and t, the specific resistance ρ of the antistatic filmis desired to be 0.1 [Ωcm] to 10⁸ [Ωcm]. Furthermore, to realize thedesired range of the surface resistance and the thickness, ρ is desiredto be 10² Ωcm to 10⁶ Ωcm.

For example, a metal oxide can be used as the material of the highresistance film 1211 having the antistatic properties. In the metaloxide, chrome-, nickel-, and copper-oxide are desired, because theseoxides are relatively small in secondary electronic emission efficiency,and can be sufficiently antistatic although an electron emitted from thecold cathode device 1012 reaches the spacer 1020. As an object otherthan a metal oxide, carbon is small in secondary electron emissionefficiency, and is desired. Especially, amorphous carbon is highlyresistant, and can be controlled to be set to a desired value of theresistance on the surface of a spacer.

The low resistance film 1221 forming the cylindrical spacer 1020 isapplied to electrically connect the high resistance film 1211 to theface plate 1017 (metal backing 1019, etc.) on the high potential sideand the substrate 1101 (wirings 1013, etc.) on the low potential side.Therefore, the plurality of functions listed below can be obtained.

1. The high resistance film 1211 is electrically connected to the faceplate 1017 and the substrate 1101.

As described above, the high resistance film 1211 is applied to providethe antistatic properties for the surface of the spacer 1020. However,when the high resistance film 1211 is connected to the face plate 1017(metal backing 1019, etc.) and the substrate 1101 (wirings 1013, 1014,etc.) directly or through the adhesive material 1041, large contactresistance arises on the surface of the connection portion, therebypossibly preventing the electric charge generated on the spacer frombeing removed rapidly. To avoid this, the connection area or the side ofthe spacer 1020 touching the face plate 1017, the substrate 1101, andthe adhesive material 1041 are provided with the low resistance film 21.

2. The potential distribution of the high resistance film 11 is leveled.

The electron emitted from the cathode device 1012 forms an electronicorbit based on the potential distribution formed between the face plate1017 and the substrate 1101. To prevent the disturbance in theelectronic orbit near the cylindrical spacer 1020, it is necessary tocontrol the entire distribution of the potential of the high resistancefilm 1211. When the high resistance film 1211 is connected to the faceplate 1017 (metal backing 1019, etc.) and the substrate 1101 (wirings1013, 1014, etc.) directly or through the adhesive material 1041, thecontact resistance on the surface of the connection point causes anuneven connection state, thereby possibly outputting a value of thepotential distribution of the high resistance film 1211 different from adesired value. To avoid this, the cylindrical spacer 1020 provides a lowresistance layer on the entire area at the end of the spacer touchingthe face plate 1017 and the substrate 1101, and a desired potential isapplied to the low resistance layer, thereby controlling the potentialof the entire high resistance film 1211.

3. The orbit of an emitted electron is controlled.

An electron emitted from the cold cathode device 1012 forms anelectronic orbit based on the potential distribution formed between theface plate 1017 and the substrate 1101. The electron emitted from thecold cathode device near the spacer may be restricted (change in wiring,device position, etc.) when a spacer is mounted. In this case, it isnecessary to irradiate an electron at a desired position on the faceplate 1017 by controlling the orbit of an emitted electron to generatean image without distortion or unevenness. A desired property can be setin the potential distribution near the cylindrical spacer 1020, and theorbit of an emitted electron can be controlled by providing a lowresistance layer on the side of the area touching the face plate 1017and the substrate 1101.

The low resistance film 1221 can be a material having a resistance valuesubstantially lower than that of the high resistance film 1211, and canbe appropriately selected from among the metal or alloy such as Ni, Cr,Au, Mo, W, Pt, Ti, Al, Cu, Pd, etc.

It is necessary for the adhesive material 1041 to be conductive so thatthe cylindrical spacer 1020 can be electrically connected to the rowdirection wiring 1013 and the metal back 1019. That is conductiveadhesive, frit glass provided with a metal particles, and conductivefillers is appropriate.

FIGS. 45 a to 45 c show the entire array of the spacers 1020. In theexample shown in FIG. 44 a, the spacers are regularly arranged as gridpoints. In the example shown in FIG. 44 b, rows of spacers adjacent toeach other in the Y direction are shifted by half pitch to each other.In the example shown in FIG. 45 c, the spacers are regularly arranged,but some spacers are not arranged. Otherwise, the spacers can bearranged at random. It is important that the spacers support theatmospheric pressure, and maintain uniform intensity without interferingelectronic beams.

(Fifth Configuration)

When spacers are used as a display panel, the arrangement of the spacerscan be designed as follows in each of the examples described below.

Example 1

FIGS. 46 to 50 show examples of the vacuum containers to which the fifthconfiguration is applied. FIG. 46 shows the outline of the vacuumcontainer of a flat panel display. FIG. 47 is a sectional view along A-Ashown in FIG. 46. FIG. 48 is a sectional view along B-B shown in FIG.46. FIG. 49 is a sectional view along C-C shown in FIG. 47. FIG. 50 is aperspective view of a spacer.

In each of FIGS. 46 to 50, reference numeral 531 denotes a frontsubstrate (T1=2.8 mm thick), reference numeral 532 denotes a rearsubstrate (T2=2.8 mm thick) mounted opposite the front substrate 531,reference numeral 533 denotes a frame mounted between two substrates andadhered airtightly. The distance D between the two substrates is 2 mm.The frame 533 is W1=112 mm long inside in the x direction, and W2=52 mmlong inside in the y direction. The frame 533 is airtightly adhered tothe front substrate 531 and the rear substrate 532 with the frit glass(not shown in the drawings). A cylindrical spacer 534 is mounted betweentwo substrates, and its cross-section is circular (R=0.1 mm in radius,and H=2 mm high). A total of 50 spacers are arranged at intervals ofP1=P2=12 mm in a square grid form.

The front substrate 531, the rear substrate 532, the frame 533, and thecylindrical spacer 534 are soda lime glass. These components form avacuum container 536.

A surface conductive electron emission device 539 is provided on therear substrate 532, and emits an electron. The rear substrate 532 isprovided with a fluorescent object 538 emitting a light by receiving anelectron to display an image. Reference numeral 537 denotes an imagedisplay area (120 mm×67 mm), and an image is formed by the lightemission of the fluorescent object 538 in the area.

In FIG. 49, A indicates an area inside the frame 533 shown in thesectional view along C-C shown in FIG. 47. Since A=W1×W2, the area is5824 mm². S indicates a total sectional area of spacers obtained byadding up the cross-sections of 50 cylindrical spacers 534, that is,S=50×π×R². Therefore, S=1.57 mm², where the support efficiency η isexpressed by the ratio S/A of 0.027%.

It is desired that the above mentioned S/A is 0.018% to 7.8%. Since theS/A according to this example is 0.027%, it is acceptable.

Now, the procedure of producing a flat panel image display device usingthe vacuum container 536 will be described.

First, the rear substrate 532 provided with the electron emission device539, etc. is set on a hot plate with the electron emission portion 533mounted upward. The frit glass is applied with a dispenser at theposition where the cylindrical spacer 534 is placed. Using an exclusivejig, the cylindrical spacer 534 is arranged on the frit glass, and thenheated so that the cylindrical spacer 534 is adhered to the rearsubstrate 532.

Then, a frame 533 to which the frit glass is applied in advance to thetop and the bottom is set on the rear substrate 532. Then, the frontsubstrate 531 on which the fluorescent object 538, etc. is provided isaligned and fixed such that the fluorescent object 538 can be set facingthe electron emission device 539. On the aligned substrate, a hot plateis placed, heated with a load up to the adhesion temperature of the fritglass, and then cooled down, thereby producing an airtight vacuumcontainer.

Although not shown, an exhaust pipe is adhered to the rear substrate 532or the front substrate 531. Then, using the exhaust pipe, the inside airis discharged by an external vacuum pump to make a vacuum of about 10⁻⁶torr. Then, the electron emission device 539 is connected to an externaldrive substrate, etc. and power is supplied to provide the function ofemitting an electron. Furthermore, a drive voltage is applied to theelectron emission device 539 to emit an electron, and a high voltage of3 kV to 15 kV is applied between the fluorescent object 538 and theelectron emission device 539 to accelerate an emitted electron to thefluorescent object 538 to be fluorescent. The light pass through thefront substrate 531. When the front substrate 531 is viewed fromoutside, an image higher in quality than in the conventional technologyis displayed on the image display area 537, thereby attaining thepurpose of this example.

Example 2

FIGS. 51 and 52 show other examples of the vacuum containers to whichthe fifth configuration is applied. FIG. 51 is a sectional view of thevacuum container of the flat panel display viewed from the side, andcorresponds to the first example of the fifth configuration shown inFIG. 49. FIG. 52 is a perspective view of the spacer.

The vacuum container 536 shown in FIG. 51 is almost the same as the thatshown in FIG. 49 except a plate spacer 535 replacing the cylindricalspacer 534. The rear substrate (T2=2.8 mm thick) 532 is positionedopposite the front substrate (T1=2.8 mm thick) 531 at intervals of D=2mm. Between the substrates, the airtightly adhered frame 533 is mounted.The area inside the frame 533 is W1=820 mm in the x direction, andW2=500 mm in the y direction. The frame 533 is airtightly adhered to thefront substrate 531 and the rear substrate 532 with the frit glass (notshown). The plate spacer 535 is one of the spacers having rectangularcross sections, and is L=40 mm long in the x direction, T=0.2 mm long inthe y direction, and H=1.8 mm high. It is provided between twosubstrates. The array of the plate spacer 535 is equal to or smallerthan 0.1 mm (substantially continuous) in interval in the x direction,P3=27.072 mm in interval in the y direction, arranged evenly andcontinuously, and 288 in number. In FIG. 51, the number of the platespacers 535 is omitted. These components form the vacuum container 536.The front substrate 531, the rear substrate 532, the frame 533 and theplate spacer 535 are soda lime glass.

A surface conductive electron emission device 539 is provided on therear substrate 532, and emits an electron. The front substrate 532 isprovided with a fluorescent object 538 emitting a light by receiving anelectron to display an image. The image display area 537 is 720.792mm×406.08 mm, and an image is formed by the light emission of thefluorescent object 538 in the area.

In FIG. 51, A indicates an area inside the frame 533 shown in thesectional view along C-C shown in FIG. 47. A=W1×W2=4.10×10⁵ mm², and Sindicates a total sectional area of 288 (=n) plate spacers 535.S=n×T×L=2.30×10³ mm². The support efficiency η is expressed by 0.56%,and this is a vacuum container with a desired configuration.

Now, the procedure of producing a flat panel image display device usingthe vacuum container 536 will be described.

First, the rear substrate 532 provided with the electron emission device539, etc. is set on a hot plate with the frame 533 mounted upward. Thefrit glass is applied with a dispenser at the position where the platespacer 535 is placed. Using an exclusive jig, the plate spacer 535 isarranged on the frit glass, and then heated so that the plate spacer 535can be adhered to the rear substrate 532.

Then, a frame 533 to which the frit glass is applied in advance to thetop and the bottom in the z direction is set on the rear substrate 532.Then, the front substrate 531 on which the fluorescent object 538, etc.is provided is aligned and fixed such that the fluorescent object 538can be set opposite the electron emission device 539. On the alignedsubstrate, a hot plate is placed, heated with a load up to the adhesiontemperature of the frit glass, and then cooled down, thereby producingan airtight vacuum container.

Although not shown, an exhaust pipe is adhered to the rear substrate 532or the front substrate 531. Then, using the exhaust pipe, the inside airis discharged by an external vacuum pump to make a vacuum of about 10⁻⁶torr. Then, the electron emission device 539 is connected to an externaldrive substrate, etc. to perform a circuit process and realize thefunction of emitting an electron. Furthermore, a drive voltage isapplied to the electron emission device 539 to emit an electron, and ahigh voltage of 3 kV to 15 kV is applied between the fluorescent object538 and the electron emission device 539 to accelerate an emittedelectron to the fluorescent object 108 to be fluorescent. The lightspass through the front substrate 531. When the front substrate 531 isviewed from outside, an image higher in quality than in the conventionaltechnology is displayed on the image display area 537, thereby attainingthe purpose of this example.

The panel spacers 535 can be arranged in a checkered form. In this case,the necessary number of spacers is 256, and S indicates a totalcross-sectional area of spacers obtained by adding up the cross-sectionsof 256 plate spacers 535, that is, S=2.05×10³ mm². The supportefficiency η is 0.50%. This is a vacuum container with a desiredconfiguration.

In addition, the vacuum container can be configured as shown in FIGS. 53and 54. In FIG. 53, the rear substrate 532 (T2=2.8 mm thick) ispositioned opposite the front substrate 531 (T1=2.8 mm thick) atintervals of substrate of 2 mm. Between the substrates, the airtightlyadhered frame 533 is mounted. The frame 533 is W1=820 mm in the xdirection, and W2=500 mm in the y direction. The frame 533 is airtightlyadhered to the front substrate 531 and the rear substrate 532 with thefrit glass (not shown). The plate spacer 535 with rectangular crosssection is provided between the two substrates (40 mm long in the xdirection, 0.2 mm long in the y direction, and 1.8 mm high in the zdirection). The array of the plate spacer 535 is equal to or smallerthan 0.1 mm (substantially continuous) in interval in the x direction,P3=27.072 mm in interval in the y direction, arranged evenly andcontinuously, and 288 in number. In FIG. 53, the number of the platespacers 535 is omitted. The front substrate 531, the rear substrate 532,the frame 533 and the plate spacer 535 are soda lime glass.

FIG. 54 shows the configuration shown in FIG. 53 with the arrangement ofthe plate spacers 535 changed into the checkered form. In this case, theinterval in the x direction is 2.55 mm, the interval in the y directionis 27.072 mm, and the number of spacers is 256.

In the configurations of the FIGS. 53 and 54, the corners of the frame533 are rounded off. The curvature is, for example, 10 mm±1.0 mm forinside diameter, and 18 mm±1.0 mm for outside diameter. With thesecurvature, the frame 533 having the rounded corner portions can beapplied for screens of 10 inches to large size such as 30 inchesdiagonally.

(Sixth Configuration)

The configuration of the frame member can be selected from varioustypes. The features of the frame member will be described here.

FIG. 55 shows an example of the frame member. The frame 533 is formed bya material having practically the same thermal expansivity as the frontsubstrate 531 and the rear substrate 532. The front substrate 531, therear substrate 532, and the frame 533 form a basic container. Both theinside and outside of the corners of the frame 533 is desired to bearc-shaped, but only the inside or outside, whichever is not limited to,can be arc-shaped. The curvature of the arc can be expressed for insideor outside. However, an inside or outside concentric circle having thecurvature of 1 to 50 mm radius is desired in intensity. The frame 533can be formed in various forming methods such as a curving process, agrinding process, a heating and pressing process, a bending process froma pole material, a punching out process, etc.

With the configuration, a color image forming device of 30 diagonal inchof the significant display area having the length-to-width (aspect)ratio of 3:4 is prepared.

FIG. 56 shows another example of a frame member. In this example, theshape of the corner portions of the frame 533 is arc only inside thecontainer. The frame 533 can be formed by grinding a soda lime materialas 3.6 mm thick, 7 mm wide, 2±0.5 mm in corner inside curvature radius.Furthermore, glass paste having a low melting point is applied by adispenser onto the joint area to the rear substrate 532, a dryingprocess is performed, and then a preprocess (provisional sintering) isperformed for 10 minutes at 380° C., thereby forming a low-melting pointglass layer. The low-melting point glass is applied using LS-3081 ofNippon Electric Glass Co., Ltd. as paste as in the process of the frontsubstrate 531.

FIG. 57 shows an example of the image display panel to which the abovementioned frame member is applied. In this example, an electron sourceis formed on the rear plate 542 by arranging a matrix of surfaceconductive electron emission devices 545, and column direction wiringand row direction wiring are formed to control the emission of electronsfrom the electron emission device 545. A face plate 543 contains afluorescent film 549 and a metal back 548 which is an acceleratingelectrode inside the glass substrate, and is arranged opposite theelectron source of the rear plate 542 through a support frame 543 of aninsulating material. A high voltage is applied from the power supply notshown between the electron source and the metal back 548. The xdirection terminals Dx1 to Dxm and the y direction terminals Dy1 to Dynextending outside the image display panel are respectively connected tothe column direction wiring and the row direction wiring. Through thewiring, an image can be displayed on the face plate 541 by controllingthe emission of electrons from the electron emission device 545according to the image information. The face plate 541, the rear plate542, and the support frame 543 are fixed to each other by frit glass,etc., to form an enclosure. Spacers 544 are provided at predeterminedintervals between the face plate 541 and the rear plate 542. The cornerportions of the support frame 543 is arc-shaped both inside and outsideof the container.

A color image forming device of 10 diagonal inch of the significantdisplay area having the length-to-width (aspect) ratio of 3:4 can beprepared by applying the configuration of the display panel describedabove. In this case, the frame can be formed as 1.6 mm thick, 13 mmwide, 10±1.0 mm in corner inside curvature radius, and 18±1.0 mm incorner outside curvature radius in the carving a soda lime glassmaterial process. The arc-shaped corner portions are concentric bothinside and outside. Furthermore, glass paste having a low melting pointis applied by a dispenser onto the joint area to the rear plate, adrying process is performed, and then a preprocess (provisionalsintering) is performed for 10 minutes at 380° C., thereby forming alow-melting point glass layer. The low-melting point glass is appliedusing LS-3081 of Nippon Electric Glass Co., Ltd. as paste as in theprocess of the face plate.

With the configuration according to the sixth configuration, a framemember can be easily formed integrally by setting as arc-shaped at leastinside or outside the container the shape of the corner portions of theframe members supporting between and at the circumferential portions ofthe face plate and the rear plate. Therefore, the slow leak at thecorner portions in the configuration of the divided frame member, or thedamage (peel-off) can be reduced, and a reliable image forming devicecan be obtained with a high yield. Furthermore, by improving theintensity of the frame member itself, the system can be easilyprocessed, thereby improving the productivity by simplifying the device,etc.

(Seventh Configuration)

The connecting portion of the configuration of the face plate, thesupport frame, and the rear plate can be designed as follows.

Example 1

This example is an example of attaining the purpose of the presentinvention for generating a large screen of an image display device.FIGS. 58 and 59 show an example of the configuration. FIG. 58 is aschematic sectional view of an airtight container, and FIG. 59 is adecomposition and perspective view of an airtight container.

In FIGS. 58 and 59, reference numeral 551 denotes a front substrate (2.8mm thick). Reference numeral 552 denotes a rear substrate (2.8 mm thick)placed opposite the front substrate 551. Reference numeral 553 denotes aframe airtightly adhered to the front substrate 551 and the rearsubstrate 553 with frit glass 555. The width W of the frame 553 is 3 mm,the thickness T is 1 mm, and the length-to-width ratio A is 3. Thethickness of the frit glass 555 is 0.2 mm. Reference numeral 556 denotesan airtight container comprising the front substrate 551, the rearsubstrate 552, and the frame 553, and reference numeral 550 denotes anairtight space. The airtight container 556 is 900 mm in the x direction,580 mm in the y direction, and 7 mm in the z direction.

Reference numeral 554 denotes a spacer for suppressing the deformationof the airtight container against the atmospheric pressure applies fromoutside when the airtight container 556 is made vacuum. The spacer 554is 0.2 mm in the x direction, 40 mm in the y direction, and 1.2 mm inthe z direction, and is fixed on one side with the frit glass 557 (0.2mm thick). FIGS. 58 and 59 show only three spacers, but there actuallyare 250 spacers. The front substrate 551, the rear substrate 552, theframe 553, and the spacer 554 are made of soda lime glass.

Reference numeral 559 denotes a surface conductive electron emissiondevice mounted on the rear substrate 552. Reference numeral 558 denotesa fluorescent object mounted on the front substrate, and becomesfluorescent by receiving an electron generated by the surface conductiveelectron emission device 559. The detailed technology about the surfaceconductive electron emission device 559 is disclosed by Japanese PatentLaid-Open No. 7-235255, etc.

Now, the method of producing the airtight container will be described.

First, the fluorescent object 558, etc. is formed on the front substrate551. Then, the surface conductive electron emission device 559, etc. areprovided on the rear substrate 552, and then the frit glass 555 and theframe 553 are laid on the rear substrate 552. Furthermore, the spacer554 and the frit glass 557 are aligned using a jig, a hot plate heatsthe frit glass 555 up to the adhesion temperature while applying a loadto the frame 553 and the spacer 554, the spacer is adhered, and thencooled. Then, the frit glass 555 and the front substrate 551 are put onthe frame 553, fixed at an appropriate position using the jig, etc., thehot plate heats the frit glass 555 up to the adhesion temperature, andthey are airtightly adhered with the frit glass 555 provided with theload. Then, they are cooled, and taken out of the hot plate, therebycompleting the airtight container 556 provided with the airtight space550.

Now, the method of producing the image display device using the airtightcontainer 556 will be described.

First, the air in the airtight space 550 is discharged using an exhaustpipe (not shown) and is kept vacuum. Then, the surface conductiveelectron emission device 559 is connected with an external drive circuit(not shown), etc., and the surface conductive electron emission device559 is electrically connected to function as an electron emission unit.Furthermore, by supplying power to display an image through an externaldrive circuit, the surface conductive electron emission device 559 emitsan electron, and the emitted electron is given to the fluorescent object558. As a result, an image can be displayed by the fluorescent object558 becoming fluorescent, thereby completing the production of the imagedisplay device.

Next, the driving process is performed in the front emission conditionwith the maximum capacity, and although the temperature of the frontsubstrate 551 and the rear substrate 552 rises no slow leak occurs inthe frame 553 and the frit glass 555, and a stable airtight containerand image display device can be obtained. Then the exhaust pipe (notshown) is cut off.

Then, the thickness T shown in FIG. 58 is set to 1 mm, on the abovementioned first condition, and the FEM analysis is performed on theframe in the range of the width of 1, 2, 5, 30, and 40 mm centering onthe width W=3 mm of the frame 553. In this analysis, the determinationstandard is the peeling-off stress σ equal to or smaller than 12 MPa atwhich a crack which causes a slow leak will not occur. Furthermore, animage display device is produced by generating an airtight containerusing the frame 553 of W=2, 5, 30, and 40 mm wide. Then the drivingprocess is performed with the maximum capacity, a slow leak is checkedusing a helium leak detector, and no slow leak is confirmed.

With an increasing value of the width W of the frame, a necessary loadto heat and adhere the frame to the front substrate and the rearsubstrate using the frit glass 555 when an airtight container isproduced also becomes large, thereby causing large consumption of aproducing device and a higher cost. As a result, it is appropriate thatthe width W is equal to or smaller than 30 mm.

Table 1 shows the above mentioned results. TABLE 1 Explanation ofExample 1 Determination Item Determination standard Width W [mm] 1 2 3 530 40 Measured value Thickness T [mm] 1 1 1 1  1  1 Measured valueLength-to-width 1 2 3 5 30 40 W/T ratio A FEM analysis x ∘ ∘ ∘ ∘ ∘ x:Stress σ > 12 Mpa ∘: Stress σ ≦ 12 Mpa Drive x ∘ ∘ ∘ ∘ ∘ x: No Example∘: No leak Practicability ∘ ∘ ∘ ∘ Δ Δ: Not practical ∘: Practical

According to this example, in the airtight container having a largescreen and the image display device using it, the fact that a slow leakhardly occurs in a practical range if the length-to-width ratio of A theframe 553 is set as 2≦W≦30 (W indicates the width of the frame), and2≦A≦30 has been proven by investigation and production.

In addition, the above mentioned ratio W/T is desired to be in the rangefrom 1.5 to 30.

Furthermore, according to this example, the spacer 554 is 40 mm long and0.2 mm thick. However, the shape and the size of the spacer is notlimited to these values. For example, it can be 200 mm long and 0.1 mmthick, or can be a cylinder of 0.1 mm in radius.

When it is applied to a large screen of 30 inch in diagonal, forexample, W=13 mm, T=1.3 mm, 0.3 mm thick frit, A=10 mm, 1.8 mm of spacerin the z direction, and 7.5 mm in capacity can be set.

Example 2

According to this example, as in the first example with the abovementioned seventh configuration, the object to successfully realize animage display device with a large screen can be attained. The componentsof this example are almost the same as those of the first example exceptthe size of the frame 553 and the spacer 554.

According to this example, the frame 553 is 12 mm in width W, 3 mm inthickness T, and the length-to-width ratio A of the frame is 4. In thisconnection, the length of the spacer 554 in the z direction is 3.2 mm.The frit glass 555 is 0.2 mm thick. The front substrate 551, the rearsubstrate 552, the frame 553, and the spacer 554 are glass having a highdistortion point.

With these units, an airtight container is produced in the same methodas the first example with the seventh configuration, and no slow leak isconfirmed in the driving process with the maximum capacity.

Furthermore, with the width W=12 of the frame, an airtight container isproduced with T=2 and 4 centering on T=3 mm to produce an image displaydevice, and investigation and confirmation are performed as in the firstexample with the above mentioned seventh configuration. Table 2 showsthe results. To change the thickness T, the length in the z direction ofthe spacer 554 is changed into 2.2 mm and 4.2 mm. TABLE 2 Explanation ofExample 2 Item Determination Determination standard Width W 12 12 12Measured value Thickness T 2 3 4 Measured value Length-to- 6 4 3 W/Twidth ratio A FEM analysis ∘ ∘ ∘ x: Stress σ > 12 Mpa ∘: Stress σ ≦ 12Mpa Drive ∘ ∘ ∘ x: No Example ∘: No leak Practicability ∘ ∘ ∘ Δ: Notpractical ∘: Practical

According to this example, in the airtight container having a largescreen and the image display device using it, the fact that a slow leakhardly occurs in a practical range if the frame 553 is set to the widthW=12, and the length-to-width ratio A as 3≦A≦6, has been proven byinvestigation and production.

With a 30 inch display unit, A=10, W=13, and T=1.3 can be set. With a 10inch display unit, A=8.6, W=12, T=1.4 can be set.

(Eighth Configuration)

The joint portion of the face plate, the frame member, the rear platecan be designed as follows. The configuration includes a firstconductive film from the area of the image forming material (fluorescentobject) of the face plate to the joint area of the frame member, and asecond conductive film from the joint area of the face plate on theframe member to the joint area of the rear plate on the frame member.This configuration can also include a third conductive film around theplurality of electron emission devices in the electron source substrateon the rear plate side and around the wiring. Furthermore, a conductivefor electrically connecting the first conductive film with the secondconductive film can be formed at the joint portion between the first andthe second conductive films, and the face plate can be adhered to theframe member with conductive frit or adhesion.

FIG. 60 shows an example of the configuration of the eighthconfiguration. In this example, a first conductive film 570 is formedaround the joint portion from an image forming material 566 on a faceplate 567 (front substrate) to a frame unit 569. On the frame unit 569,a second conductive film 571 is formed from an joint portion with theface plate 567 to a joint portion with the rear plate (substrate) 564.The first conductive film 570 is electrically connected to the secondconductive film 571 at the joint portion, and a conductive material 572for guaranteeing the electrical connection can also be formed. Withoutthe conductive material 572, the electrical connection can also beguaranteed using conductive frit glass obtained by mixing an adhesivematerial 574 with conductive filler such as Au, Ag, etc.

The joint portion between the second conductive film 571 and the rearplate 564 is desired to be maintained with the potential substantiallyequal to that detected when an electron source 562 is driven. Forexample, as shown in FIG. 60, an electrode 573 can be formed in contactwith the conductive film at the end of the joint area with the rearplate 564 of the frame unit 569. In this case the electrode 573 is, forexample, connected to the ground potential.

The first conductive film 570 is formed with the surface resistance Rs(sheet resistance) equal to or smaller than 10¹¹Ω/□. The sheetresistance Rs is a value obtained when the resistance value R as R=Rs(1/w) measured in the length direction of the film having the thicknessof t, the width of w, and the length of 1. If the resistance rate if ρ,then Rs=ρ/t. The sheet resistance Rs is set in the above mentioned rangebecause it is desired that the Rs is equal to or smaller than 10¹¹Ω/□ tobe antistatic against the above mentioned ion, etc. It is desired thatthe sheet resistance of the second conductive film 571 is 10⁸Ω/□ to10¹¹Ω/□ also because it is desired that the Rs is equal to or smallerthan 10¹¹Ω/□ to be antistatic against the ion, etc., and because thatthe Rs is equal to or larger than 10⁸Ω/□ to reduce the power consumed bythe electric current flowing through the second conductive film 571 whena high voltage is applied to the image forming material 566.

By appropriately setting the sheet resistance of the first conductivefilm 570 and the second conductive film 571 in the above mentioned rangein consideration of the structure parameter around the frame unit 569,the disturbance of the electric field around the frame unit can becontrolled. Assume that the value of the high voltage applied to theimage forming material 566 is Va, the distance from the end point of theimage forming material 566 to the joint portion to the frame unit is L,the height of the frame unit is H, and the sheet resistance values ofthe first and the second conductive films are Rs1 and Rs2. For example,to set the potential of Va/2 at the joint portion between the frontsubstrate and the frame unit, Rs1/Rs2=H/L. In addition, if Rs1/Rs2 isset to the smallest possible value, the balanced parallel in electricfield between the image forming material 566 and the electron source 562can continue around the frame unit as shown in FIG. 60.

When substantially parallel equipotential planes are formed between thefront substrate and the rear substrate as shown in FIG. 60, the distancebetween the frame unit and the image forming unit can be shortenedwithout apparently affecting the orbit of an emitted electron. As aresult, the ratio of the image display area to the entire display devicecan be preferably larger. To form above mentioned equipotential planes,the value of Rs1/Rs2 is set to a smallest possible value.

Furthermore, when a spacer is mounted between the front substrate andthe rear substrate with the surface sheet resistance controlled, thesheet resistance of the surface of the frame unit is equal to that ofthe spacer. Furthermore, the first conductive film and the metal backare extended to the frame unit. With this configuration, the potentialapplied to the metal back is applied to the end portion (upper end) ofthe front substrate side of the spacer and the end portion (upper end)of front substrate side of the frame unit.

Furthermore, by setting an equal potential at the end portion (lowerend) of the rear plate side of the frame and at the end portion (lowerend) of the rear substrate side of the spacer, the surface of the frameunit and the surface of the spacer have substantially the same potentialdistribution.

With the above mentioned settings, substantially parallel equipotentialplanes can be formed between the front plate and the rear plate.

As a forming material of the above mentioned conductive film, a carbonmaterial, metal oxide such as tin oxide, chrome oxide, ITO, etc.,conductive materials dispersed into silicon oxide, etc. can be used.These materials are appropriate because they can easily form an evenfilm over a large area.

The first conductive films 570 and 571 can be formed in the spatteringmethod, the vacuum vapor deposition method, the application method, theelectrical beam polymerizing method, the plasma method, the CVD method,etc. In any of these methods, a stable conductive film can be easilyobtained.

FIG. 61 shows the second example of the display plate according to thepresent invention. In FIG. 61, the units also shown in FIG. 60 areassigned the same numbers. The image forming device shown in FIG. 61 isdifferent from the image forming device shown in FIG. 60 in that a thirdconductive film 576 is formed at least on the surrounding insulatingsubstrate of the electron source 562 and wiring 563 formed on theinsulating substrate of glass, etc.

With the configuration, the third conductive film can be formed on theabove mentioned rear plate in an area not provided with the conductivefilm and the electrode, for example, on the surface of the substrate 561between the wiring in the x direction, between the wiring in the Ydirection, and between respective electron emission devices. Since thethird conductive film is electrically connected to the electrodepotential, grand potential, etc. such that the potential can be close tothat of the drive voltage of the electron emission device, thedistortion and the fluctuation of the electronic beam orbit due toaccumulation of electrical charge at the areas can be suppressed. It isdesired that the sheet resistance of the third conductive film is equalto or smaller than 10¹¹Ω/□ from the viewpoint of aiming at antistaticproperties, and it is also desired that it is equal to or larger than10⁸Ω/□ from the viewpoint of reserving each wiring and insulationbetween electrodes and reducing insignificant power consumption by aleak current. The material forming the third conductive film and themethod of forming a film can be the same as the material and the methodof the first and the second conductive films.

Since the third conductive film 576 is set to a resistance value forreserving the insulation between each wiring and electrode, the film canbe formed on the entire rear substrate forming an electron source, orthe third conductive film can be formed on the substrate 561 in advance,and the electron source 562 and the wiring 563 can be formed thereon.

Next, the joint portion produced, for example, in the configurationshown in FIG. 60 or 61 will be described. First the face plate 567 isproduced as an image display portion. On one side of a glass substrate565 of the face plate 567 is provided with a transparent electrodecomprising an ITO in advance. The ITO film functions as the firstconductive film according to the present invention, and the sheetresistance is 2×10³Ω/□.

The image forming material 566 is an image forming material, has stripesof fluorescent object for realizing a color, and first forms a blackstripe so that the fluorescent film 566 can be produced by applying afluorescent object of each color to the space area in the slurry method.As a material of the black stripe, a commonly used material mainlycontaining graphite is adopted. In addition, a metal back is provided onthe surface of the fluorescent film 566 facing the electron source. Themetal back is produced by performing smoothing process (normallyreferred to as a filming process) on the inside surface of thefluorescent film 566 after producing the fluorescent film 566, and thenperforming a vacuum vapor deposition of Al.

Then, the frame unit 569 is produced. The frame unit 569 is made of sodalime glass, and the second conductive film made of chrome oxide isgenerated by an electron beam assisted vapor deposition process. Thesheet resistance is set to 3×10¹⁰Ω/□. Then, an electrode of an Al vapordeposition film is formed over the adhesion plane to be adhered to therear substrate of the frame unit 569 and the end of the secondconductive film.

As described above, the produced face plate 567 is mounted through theframe unit 569 3 mm above the rear substrate which is formed with anumber of surface conductive electron emission devices, and theconductive frit glass obtained by mixing the filler of Au particles isapplied to the joint portion between the face plate 567 and the frameunit 569, and normal (insulating) frit glass is applied between theframe unit 569 and the rear plate 564, and is then sintered for 10minutes in the atmosphere at 410° C.

Furthermore, with the configuration using the third conductive film,first, the third conductive film is formed on the front plane on whichthe electron source of the above mentioned rear substrate is formed byRF magnetron sputtering. The used target is carbon and the filmthickness is about 2 nm. The sheet resistance value at this time is5×10⁸Ω/□ approximately. Then, after forming an image forming materialcomprising the fluorescent film 566 and the metal back, the firstconductive film 570 comprising a carbon thin film is formed on the glasssubstrate around the image forming material. The first conductive film570 is formed by spraying the solution obtained by dispersing the carbondispersion material having the particle diameter of 0.1 μm in an organicsolvent. The carbon dispersion material mainly contains graphite havingan additive of TiO₂ to reduce the conductivity. After the application, aheating process is performed at 200° C. to stabilize the carbon thinfilm. The thus generated first conductive film is about 1 μm thick, andthe sheet resistance is 2×10⁷ Ω/□.

Furthermore, the frame unit 569 is produced. The frame unit 569 is madeof soda lime glass, and the second conductive film comprising tin oxideis formed by the electron beam assisted vapor deposition process. Thesheet resistance is set to 2×10¹⁰Ω/□. Then, an electrode of an Al vapordeposition film is formed over the adhesion plane to be adhered to therear substrate of the frame unit 569 and the end of the secondconductive film. In the above mentioned operation, the configurationusing the first to third conductive films can be obtained.

(Ninth Configuration)

There can be various configurations as the configuration of the spaceritself. For example, the configuration shown in FIG. 62 can be adopted.Such a spacer has the following features.

PD glass has the thermal expansivity similar to that of the soda limeglass used for a face plate, a rear plate, and a frame memberconstituting an enclosure of the vacuum container. Therefore, a displaypanel hardly generates destruction or distortion during the displaypanel assembling process or the heating process in the vacuum process.In addition, the movement of the electric charge in the high electricfield (several kV/mm) is considerably small than in the soda lime glass.Therefore, at a high voltage applied between the anode electrode on theface plate and the electron source on the rear plate, there is littledischarge along the spacer or deterioration in the spacer material.Therefore, the reliability of the spacer material and the display panelcan be greatly improved.

An electrode can be formed for two planes touching the face plate andthe rear plate and/or a part of the side portion of the spacer in thefollowing process.

(a) After a mask having an opening corresponding to a spacer electrodeforming portion is aligned and set proximate to the spacer, it is set inthe spattering film forming device.

(b) After evacuating the spattering film forming device, and a desiredvacuum is attained, a desired target material is spattered with adesired ionized gas, and a desired material is applied as a film on thesurface of the spacer.

(b-1) Ti is used for a base layer by spattering a titan target in anargon gas to form a film.

(b-2) Pt is used for a spacer electrode by spattering a platinum targetin an argon gas to form a film.

Titan used for a base layer has the function of improving the adhesionbetween the glass (including an oxide) spacer substrate and platinumwhich hardly become oxidized. Since the platinum low resistance film(spacer electrode) touches the high resistance film, the material hasbeen selected because the quality deterioration hardly occurs in thehigh resistance film and its boundary portion in the display panelproducing process (especially in a heating process) and the high voltageapplying process.

The above mentioned low resistance film (spacer electrode) has thefunction of maintaining the electric connection between the spacer, theanode on the face plate, and the wiring on the rear plate for the entirespacer, the function of perform a desired controlling process on theelectron orbit around the vicinity of the spacer, and the function ofproviding antistatic properties for the spacer by controlling thesecondary electron emission on the surface of the spacer using a lowresistance material having a low secondary electron emissioncoefficient.

Then, a high resistance film having the antistatic properties is formedon the spacer surface exposed in the display panel forming a vacuumcontainer. In the high resistance film forming process, the spatteringfilm forming device is first evacuated. When a desired vacuum isobtained, the desired target material is spattered by an ionized gas,and the surface of the spacer is covered with a film of a desiredmaterial. For example, aluminum nitride is used as a base layer, and analuminum target is spattered in a nitrogen gas to form a film (200 to500 Å) Then, a tungsten target and a germanium target are simultaneouslyspattered in a nitrogen gas, thereby forming a film (500 to 3000 Å)using a tungsten nitride and germanium alloy composite (WGeN) as a highresistance film.

This high resistance film has the function of controlling the amount ofthe secondary electron generated on the surface of the spacer by thecrash of the electron emitted from an electron source on the rear plate,an electron reflected by the anode of the face plate, other ionizedsubstances, or the ultraviolet and X-ray based on the secondary electronemission properties of a high resistance film, and the surfacestructure, and suppressing the accumulation of electric charge.Furthermore, by appropriately controlling the resistance value of a highresistance film, and a generated electric charge can be quickly removed,thereby appropriately reducing the heat by the electric current at ahigh electric field.

(10th Configuration)

When a getter is provided in a container as means for maintaining avacuum in the vacuum container of a display panel using a spacer, a typeof getter can be included in the configuration between spacers. FIG. 63shows an example of the configuration. FIG. 63 a is a perspective viewof an image forming device. FIG. 63 b shows a type of the arrangement ofthe getter and the spacers. FIG. 63 c is a sectional view along C-C′shown in FIG. 63 b.

In FIG. 63, reference numeral 581 denotes an electron source provided byarranging a plurality of electron emission devices on a substrate withwiring appropriately set. Reference numeral 582 denotes a rear plate.Reference numeral 583 denotes a support frame. Reference numeral 584denotes a face plate. Reference numeral 589 and 594 denote getters.Reference numeral 595 denotes a plate spacer. The rear plate 582, thesupport frame 583, the face plate 584, and the plate spacer 595 areadhered to each other with frit glass, etc. applied on each jointportion, thereby forming an enclosure. Inside the face plate 584, ametal back and a fluorescent object 587 are mounted.

On the above mentioned face plate and an electron source substrate, thegetter 589 is mounted between spacers on the metal back or the blackconductive material on the face plate side, or on the wiring in the xdirection on the electron source substrate. A getter can be mounted oneither side or on both sides. It is desired that the getter mountingareas are distributed evenly in the whole image display area.Furthermore, the are on which the getter 589 is mounted is desired to belarger than the mounting area of the plate spacer 595, electron source581, and the image forming material.

On the other hand, the position of the getter 594 can be either on theface plate 584 or the rear plate 582 or on both plates if it isinsulated from the metal back and an electron source inside the imageforming device and outside the image display area.

It is desired that the spacer is located on the wiring from theviewpoint of the setting area and the electro-optical viewpoint. Thus,the settings do not affect the arrangement of electron emission devices.when the getter 589 is arranged on the electron source substrate side,it is preferably arranged on the wiring as in case of the spacers. Whenthe getter is arranged on the wiring, for example, as shown in FIG. 63,it is desired to set it at an area other than the area where the spacersare arranged because a part of the getter can be covered with thespacers if the spacers are arranged on the getter located on the wiring,thereby reducing the area for the getter.

When a plurality of spacers are provided, it is desired to arrange themon the wiring between the plurality of spacers such that a part of thegetters cannot covered with the spacers.

When the wiring is a matrix wiring as the row direction wiring and thecolumn direction wiring, the wiring on which the getter is arranged canbe either the row direction wiring or the column direction wiring, orthe getter can be arranged on both of them.

The material of the getters 589 and 594 can be one or more kinds ofmetal among Ti, Zr, Cr, Al, V, Nb, Ta, W, Mo, Th, Ni, Fe, or Mn, or analloy of them. Otherwise, the getter can be Ba covered with anappropriate mask, and can be processed in the vacuum vapor depositionmethod, the spattering method, the getter flash method. Now, an exampleindicating a feature in arranging a getter will be described.

Example 1

With the configuration shown in FIGS. 63 a to 63 c, a getter layer 1409comprising a Zr—V—Fe alloy is formed on an upper wiring 1402 in an imagedisplay area in the spattering method using a metal mask. The getterlayer 589 is adjusted to be 2 μm thick and 400 μm wide, that is, widerand longer than the plate spacer which is 200 μm width. In this example,a non-evaporation getter is formed. The composition of the adoptedspattering target is Zr for 70%, V for 25%, and Fe for 5% in weightratio.

Example 2

FIG. 64 shows another example of this configuration. FIG. 64 a is aperspective view of an image forming device. FIG. 64 b shows a type ofthe arrangement of the getter and the spacers. FIG. 64 c is a sectionalview along C-C′ shown in FIG. 64 a. In FIG. 64, the configuration alsoappearing in FIG. 63 is assigned the same reference numerals.

In this example, the getter layer 589 of Ti—Al alloy is formed in thespattering method on all black matrixes 592 of the face plate 584. Thegetter layer 1409 of the Ti—Al alloy is 5 μm thick, and is wider andlonger than the plate spacer of 150 μm width. The composition of thealloy target in the spattering process is Ti for 85% and Al for 15%.

Example 3

FIG. 65 shows another example of this configuration. FIG. 65 a is aperspective view of an image forming device. FIG. 65 b shows a type ofthe arrangement of the getter and the spacers. In FIG. 65, theconfiguration also appearing in FIG. 63 is assigned the same referencenumerals.

In this example, the image forming device is the same as that accordingto the first example with the above mentioned configuration except thatthe evaporation getter is in a wire form and the getter flash isperformed in a resister heating process.

Example 4

FIG. 66 shows another example of this configuration. FIG. 66 a is aperspective view of an image forming device. FIG. 66 b shows a type ofthe arrangement of the getter and the spacers. FIG. 66 c is a sectionalview along C-C′ shown in FIG. 66 b. In FIG. 66, the configuration alsoappearing in FIG. 63 is assigned the same reference numerals.

In this example, the plate spacer of 20 mm long is arranged on thewiring in the image display area in a checkered form at intervals of 50mm, and the getter 589 is formed between spacers. Otherwise, the imageforming device has the same configuration as the first example.

Example 5

FIG. 67 shows another example of this configuration. FIG. 67 a is aperspective view of the image forming device. FIG. 67 b shows thesectional view of the image forming device.

According to this example, the image forming device is the same as thatin the first example except that the getter 589 is formed on the upperwiring 1402 and the black matrix 592 in combination use of the processesin the first and second examples of the above mentioned configurations.

According to the above mentioned tenth configuration, the mounting areaof the getter material is set larger than the mounting areas of theplate spacer, the electron source substrate, and the image formingmaterial. Therefore, the getter material can be mounted in a larger areaand near the area in which a gas is discharged. As a result, a gasemitted in an enclosure is quickly adsorbed by the getter material, avacuum in an enclosure is well maintained, and the amount of emittedelectrons from the electron emission device can be stabilized.Therefore, the deterioration of the features can be reduced, and thereduction of the intensity when a long term operation is performed,especially around the outside the image display area, can be lowered,and the uneven intensity can be reduced.

(11th Configuration)

The arrangement of the getter can be designed as follows. That is,

(1) First, in a display panel having an electron source substrate, aplurality of electron emission devices arranged in a matrix form on asubstrate, connected through wiring with an opposite electrode, and, inan enclosure, an image forming material having a fluorescent filmprovided face to face with the substrate, wherein a non-evaporationgetter is formed on the wiring of the electron source substrate, and theelectric resistance between arbitrary two points of the continuousnon-evaporation getters is higher than the electric resistance of thewiring on which the non-evaporation getter between the two points isformed.

(2) Second, the simple matrix wiring method applied to the abovementioned electron source substrate is realized by a scanning sidewiring connecting one of the opposite electrodes and a signal sidewiring connecting the other, the wiring on which the non-evaporationgetter is formed is a scanning side wiring of the electron sourcesubstrate.

With this configuration, if the wiring portion forming thenon-evaporation getter (NEG) and the wiring portion not forming the NEGcoexist, the uneven voltage drop for each wiring portion can be reduced.Therefore, the uneven intensity by forming non-evaporation getter can beminimized, so the getter material can be arranged on the wiring near thegas emitting portion as well. As a result, the gas generated in theenclosure after the sealing process can be quickly adsorbed by thegetter material, and the vacuum in the enclosure can be well maintained,thereby stabilizing the amount of emitted electrons from the electronemission devices. In the case of the electron source substrate of thesimple matrix wiring, the getter material can be designed to be formedon both scanning side wiring and signal side wiring, or on only onewiring side. When it is formed on one side, it is desired that thegetter is formed on the scanning side wiring because, in the case of thesimple matrix drive, it is desired that a larger amount of electriccurrent flows in the X direction wiring, which is a scanning wiring,than in the Y direction wiring which is a signal wiring, thereby makinga wider X direction wiring, and a larger NEG forming area.

FIGS. 68 and 69 show a type of the configuration in whichtwo-dimensional array of electron sources are connected through matrixwiring. FIG. 68 is a plan view. FIG. 69 is a sectional view along A-A′shown in FIG. 68. Reference numeral 1502 denotes an X direction wiring(scanning side wiring, upper wiring), and reference numeral 1503 denotesa Y direction wiring (signal side wiring, lower wiring). They arerespectively connected to an electron emission device 1508 throughdevice electrodes 1505 and 1506. The interconnection between the Ydirection wiring 1503 and the X direction wiring 1502 has an insulationlayer 1504 formed on the Y direction wiring 1503. The X direction wiring1502 is formed on them. The X direction wiring 1502, the Y directionwiring 1503, the device electrodes 1505 and 1506, and the electronemission device 1508 are formed by the combination of the photolithoprocess and the vacuum vapor deposition method, the planting method, theprinting method, the method of resolving metal in a solution, providinga drop of the solution, and sintering it, etc.

Non-evaporation getters (NEG) 1509 and 1510 are formed on the wiring ofthe electron source substrate. The non-evaporation getter can be formedin both X direction (scanning side wiring, upper wiring) and Y direction(signal side wiring, lower wiring), and can be formed only in onedirection. When it is formed on one direction, it is desired to beformed on the X direction wiring because, in the case of the simplematrix drive, it is desired that a larger amount of electric currentflows in the X direction wiring, which is a scanning wiring, than in theY direction wiring which is a signal wiring, thereby making a wider Xdirection wiring, and a larger NEG forming area. It is desired that itis evenly distributed in the entire image display area (therefore, thepresent getter is referred to as an internal display area getter).

The material of the non-evaporation getter (NEG) formed on the wiringcan be one or more kinds of metal among Ti, Zr, Cr, Al, V, Nb, Ta, W,Mo, Th, Ni, Fe, or Mn, or an alloy of them. The getter can be producedby the patterning through the photolitho process, the vacuum vapordeposition method, or the spattering method. The non-evaporation getter(NEG) can also be produced using one or more kinds of metal selectedfrom the above mentioned getter materials, or the alloy of them, or bymixing them with another kind of metal, non-metal material, etc. byprinting process in the screen method and the offset method, and usingthe plating method, etc.

The electric resistance between continuous arbitrary two points of anon-evaporation getter is set to be higher than the electric resistancebetween the two points of the wiring below the non-evaporation getter.It is thus designed because a larger electric current flows through thenon-evaporation getter than through the wiring, thereby changing thevoltage dropping substantially, and generating uneven intensity of theimage forming device when the electric current flows through thenon-evaporation getter mainly made of metal at the upper portion whenthe electric current flows through the wiring when it is driven in theenergization forming process and the activating process in the deviceforming process described later in the image forming device containing awiring portion forming the non-evaporation getter and the wiring portionnot forming the non-evaporation getter. When the electric resistancebetween continuous arbitrary two points of a non-evaporation getter isset to be higher than the electric resistance between the two points ofthe wiring below the non-evaporation getter, there is small unevennessof voltage drop between the wiring portion forming a non-evaporationgetter and the wiring portion not forming it, and the uneven intensitycan be reduced.

Next, an example of the eleventh configuration will be described.

Example 1

FIG. 70 shows the configuration of the image forming device to which theeleventh configuration is applied. FIG. 70 a is a perspective view. FIG.70 b is a top view. In these figures, the units also shown in FIG. 68are assigned the same reference numerals.

Reference numeral 621 denotes an electron source, and is obtained byarranging a plurality of electron emission devices on a substrate withappropriate wiring. Reference numeral 622 denotes a rear plate.Reference numeral 623 denotes a support frame. Reference numeral 624denotes a face plate. These units are adhered to each other using a fritglass, etc. at respective joint portions, thereby forming an enclosure.A metal back and a fluorescent object are arranged inside the face plate624.

The display panel according to this example includes non-evaporationgetters (NEG) on the X direction wiring (upper wiring) and the Ydirection wiring (lower wiring) every second position as shown in FIGS.70 a and 70 b. The display panel according to this example also includeson the substrate an electron source containing a plurality of (100rows×300 columns) surface conductive electron emission devices in asimple matrix wiring. FIGS. 68 and 69 show partial plan views of theelectron source.

An electron source substrate 1501 comprises the X direction wiring 1502(upper wiring, also referred to as a scanning side wiring) providedcorresponding to Dox1 to Doxn, the Y direction wiring 1503 (lowerwiring, also referred to as a signal side wiring) provided correspondingto Doy1 to Doyn, the electron emission device 1508, the deviceelectrodes 1505 and 1506, the inter-layer insulation layer 1504, thenon-evaporation getters 1509 and 1510. Each of the non-evaporationgetters 1509 and 1510 is adjusted to be 2 μm thick. Using the thicknessof the film, the resistance value of the non-evaporation getter betweenthe arbitrary two points on the film of the continuous non-evaporationgetters is higher than the resistance of the wiring between the lowertwo points.

The resistance ratio (volume resistance ratio) of the lower and upperwiring is 5×10⁻⁸ Ωm, and the volume resistance ratio of one getter is4.1×10⁻⁷ Ωm. The sectional area of the lower wiring at a given point is1000 μm², the sectional area of the getter is 100 μm², and theresistance values at intervals of 1 cm are 0.5Ω and 20.5Ω. With theconfiguration, the resistance value of the getters is sufficientlylarger than the resistance value of the lower wiring. In addition, thesectional area of the upper wiring at a given point is 1500 μm², thesectional area of the getter is 100 μm² and the resistance values atintervals of 1 cm are 0.33Ω and 20.5Ω. With the above mentionedconfiguration, the resistance value of the getter can be sufficientlylarger than the resistance value of the upper wiring.

In this example, the method of forming a non-evaporation getter can bethe photolitho process, and the spattering film forming method. However,the present invention is not limited to these methods. That is, similareffects can be obtained by the patterning method using a metal mask, amethod of drawing with adhesives using a dispenser and printing, andadhering the powder of a non-evaporation getter, the plating method,etc. The similar methods can be used with the effect described belowwhen an arbitrary pattern is to be formed in addition to the pattern ofarranging the NEGs at every second position.

Example 2

FIG. 71 shows another example of the image forming device to which theeleventh configuration is applied. FIG. 71 a is a perspective view, andFIG. 71 b is a top view. In these figures, the components also shown inFIGS. 68 and 70 a, and 70 b are assigned the same reference numerals.The configuration is different from the above mentioned first example ofthis configuration in that the non-evaporation getter is formed at everysecond position only on the X direction wiring (upper wiring).

According to the above mentioned eleventh configuration, in the imageforming device having an electron source substrate on which a pluralityof electron emission devices are arranged in a matrix form on thesubstrate and wired, and a fluorescent film provided opposite to thesubstrate, a getter material is mounted near the gas emitting portion ina large range by forming a non-evaporation getter on the wiring of theelectron source substrate of the image forming device. In this case,since it is not necessary to provide a vaporizing source of the gettermaterial above the wiring, the electronic orbit is not affected when thesystem is driven, the gas generated in the enclosure after the sealingprocess can be quickly adsorbed, and the vacuum in the enclosure can bewell maintained, thereby stabilizing the amount of emitted electronsfrom the electron emission devices, and reducing the deterioration ofthe features. Therefore, the reduction of the intensity when a long timeoperation is performed, especially the reduction of the intensity nearoutside the image display area, and the uneven intensity can besuppressed.

When a non-evaporation getter is formed, the electric resistance of thenon-evaporation getter is set to higher than the electric resistance ofthe wiring so that the uneven voltage drop can be reduced even whenthere are some wiring portions on which a non-evaporation getter isformed and others on which a non-evaporation getter is not formed. As aresult, the uneven intensity of the image forming device can be reduced.

In the activating process of a getter, there is no need of performingthe vaporizing getter incorporating process and the getter flashprocess, thereby performing only the heating process to produce an imageforming device with good yield.

(12th Configuration)

The following configuration can be designed as an aspect of arranging agetter. That is, in a display panel forming an enclosure by arrangingthe electron source substrate having a plurality of electron emissiondevices, and the emission display substrate having an image formingmaterial face to face, a non-evaporation getter (NEG) can be continuallyprovided on the wiring formed for the electron source substrate.

With the configuration, the length of one NEG unit provided on thewiring, etc. is rather short to make a continuous body. Therefore, thestress occurring in the film is not large. As a result, the NEG can beprevented from being peeled off, and there are no destruction in theeven distribution of the NEG over the image display area. As a result,the pressure distribution in the image display device can be evenlymaintained. In addition, not only the NEG, but also each wiring arrangedthereunder can be prevented from being peeled off or disconnected.Furthermore, the peeled-off NEG or the portion where an NEG film is notfully peeled off but partially detached can be prevented from being atrigger of break down discharge or short-circuit. Thus, the yield offorming an image display device can be enhanced.

Furthermore, the length of the continually set NEG unit can be shorterthan the pitch of picture elements of the electron emission devices, orcan be equal to the pitch of the picture elements of the electronemission devices.

Since the display panel has electron emission devices arranged in atwo-dimensional array, the wiring for providing electric energy or asignal can have a number of intersecting portions of layer wiring asrepresented by the matrix wiring. The intersecting portions have a gapwithout a smoothing process. For example, as shown in FIG. 72 a, theportion 21 at the intersection between the lower wiring 21 b and theupper wiring (including the NEG) 21 a is subject to a disconnection bythe stress of the film. In addition, as shown in FIG. 72 b, there is thepossibility that the insulation is lost at a non-contact portion such asa portion 22 at the intersection portion between the lower wiring 22 band the upper wiring (including the NEG) 22 a. Especially, each time aconductive material is increased and laid at the intersection point,there arises the strong possibility described above. The NEG is metal,and is desired to be thicker. Therefore, mounting the NEG on the wiringintersection portion invites a disconnection and a short circuit betweenthe upper and lower wiring.

In addition, when the NEG is continuously mounted on a long pattern aswiring in the NEG film generating process, the turn-over of the NEGmaterial can be predicted if a mask depo using a metal mask is assumed(refer to FIG. 73 a). In FIG. 73 a, A indicates a mask being peeled-off,and B indicates the distortion of the mask.

With the above mentioned configuration, the length of the NEG is equalto or shorter than the pitch of the picture element. Therefore, it canbe mounted as not overlapping the above mentioned intersection of thewiring, thereby easily avoiding the possibility of a disconnection or ashort circuit. In addition, when a metal mask is used, the effectobtained when a reinforcing pattern for a mask is provided incorresponding to the discontinuous portion of the NEG film can beobtained, thereby avoiding the turn-over of the NEG material (refer toFIG. 73 b). As a result, the yield of forming an image forming devicecan be enhanced. Now, an example of this configuration will bedescribed.

Example 1

FIG. 74 is a perspective view of a type of an example of the imageforming device to which the twelfth configuration is applied. Referencenumeral 641 denotes an electron source obtained by arranging a pluralityof electron emission devices on a substrate with appropriate wiring.Reference numeral 642 denotes a rear plate. Reference numeral 643denotes a support frame. Reference numeral 644 denotes a face plate.They are adhered to each other using frit glass, etc. at respectivejoint portions, and form an enclosure. Reference numeral 652 denotes agetter. An NEG film 649 is divided and mounted on the entire area of theX direction wiring (upper wiring) in the image display area. Inside theface plate 644 are arranged a metal back and a fluorescent object.

FIG. 75 shows a partial plan view of the electron source 641. FIG. 76 isa sectional view along B-B′ shown in FIG. 75. The components also shownin FIGS. 75 and 76 are assigned the same reference numerals.

Reference numeral 81 denotes an electron source substrate. Referencenumeral 82 denotes an X direction wiring (also referred to as upperwiring) corresponding to Dox1 to Doxn shown in FIG. 74. Referencenumeral 83 denotes a Y direction wiring (also referred to as lowerwiring) corresponding to Doy1 to Doyn shown in FIG. 74. Referencenumeral 88 denotes a conductive film containing an electron emissionunit. Reference numeral 89 denotes an electron emission unit. Referencenumerals 85 and 86 denote device electrodes. Reference numeral 84denotes an inter-layer insulating layer. Reference numeral 87 denotes acontact hole for electrically connecting the device electrode 85 withthe lower wiring 83.

In this example, a metal mask whose plural openings are formed in eachrow is aligned along the X direction wiring (upper wiring) and fixed onthe electron source substrate 81. The openings are 6.7 mm long and 240μm wide, and arranged at intervals of 0.89 mm in the X direction wiringfor full length. The masked electron source substrate 81 is mounted inthe spattering device. A target is an alloy of Zr—V—Fe=70 wt %:25 wt %:5wt %, and an alloy layer of 1 μm thick is formed in the spatteringmethod as an NEG film 810.

Example 2

In this example, a metal mask whose plural openings are formed in eachrow is aligned along the X direction wiring (upper wiring) and fixed onthe electron source substrate 81. The openings are 490 μm long and 240μm wide, and arranged at intervals of 200 μm in the X direction wiringfor full length. The masked electron source substrate 81 is mounted inthe spattering device. A target is an alloy of Zr—V—Fe=70 wt %:25 wt %:5wt %, and an alloy layer of 1 μm thick is formed in the spatteringmethod as an NEG film 1210 (refer to FIG. 77).

Example 3

In the following process, an electron source for a display panel isproduced based on the configuration shown in FIG. 74.

Step-A

First, the electron source substrate 641 is sufficiently cleaned using acleaner, pure water, and organic solvent. In the sputtering method, Ptis piled for 0.1 μm, and is processed by the photolithography technologyto form an device electrode of L=2 μm in electrode intervals, W=300 μmlong on the electron source substrate 641.

Step-B

Then, Ag paste ink is printed and sintered to form a Y direction wiring1503 of 270 μm wide and 8 μm thick.

Step-C

Next, glass paste is printed and sintered (at 550° C. sinteringtemperature) to form an SiO₂ inter-layer insulating film of 20 μm thick.

Step-D

Furthermore, Ag paste is printed and sintered to form the X directionwiring 1502 of 340 μm wide and 12 μm thick.

Step-E

The same as the process according to the first example of the abovementioned configuration.

Step-F

After applying the photo-resist (AZ4620 of Hoechst) to the electronsource substrate 641 while turning it with a spinner, a metal mask whoseplural openings are formed in each row and column is aligned along the Xdirection wiring (upper wiring) and the Y direction wiring (lowerwiring), and provisionally fixed on the electron source substrate 641.The openings are 6.7 mm long and 240 μm wide, and arranged at intervalsof 0.89 mm in the X direction wiring for full length. After baking itfor 30 minutes at 90° C., the metal-masked electron source substrate 641is exposed and developed, and the resist at the openings is removed.

Step-G

The masked electron source substrate 641 is set in the plasma solutioninjecting device. At the powder providing unit (hopper) of the device isloaded with the getter powder ST707 (SAYES) of Zr—V—Fe=70 wt %:25 wt %:5wt %, and the powder is provided for the Ar plasma using a flow gas asAr to form an NEG layer of 50 μm thick.

Step-H

The electron source substrate 641 covered with the NEG film is put inthe resist peeling solution (microposit remover) to remove the NEG withthe metal mask except at the opening, thus performing the NEG patterningprocess.

Thus, the electron source 641 provided with internal display area getteris formed.

Example 4

After applying the photo-resist (AZ4620 of Hoechst) to the electronsource substrate while turning it with a spinner, a metal mask whoseplural openings are formed in each row is aligned along the X directionwiring (upper wiring), and provisionally fixed on the electron sourcesubstrate. The openings are 490 μm long and 240 μm wide, and arranged atintervals of 200 μm in the X direction wiring, and 250 μm long and 100μm wide, and arranged at intervals of 440 μm in the Y direction wiring.After baking it for 30 minutes at 90° C., the metal-masked electronsource substrate is exposed and developed, and the resist at theopenings is removed.

According to the above mentioned twelfth configuration, there aresubstantially no peeled-off film or short circuit between upper andlower wiring, and the uneven intensity can be reduced in the imageforming area. In addition, a fault due to break down discharge, etc. canbe suppressed, thereby improving the yield of a display panel.

(13th Configuration)

Now, another example of an aspect of arranging getters will bedescribed. This configuration is featured by the arc-shaped section ofthe non-evaporation getter. It is desired that the non-evaporationgetter is arranged on the scanning side wiring or the signal side wiringto apply a voltage to an electron emission device, and is arrangedwithin a range smaller than any wiring width. Furthermore, it isfeatured by the non-evaporation getter positioned closer to the anodeside than the insulation layer for insulation between the scanning sidewiring (upper wiring) and the signal side wiring (lower wiring), and bythe non-evaporation getter positioned lower than the anode in theenclosure.

According to this configuration, when a gas discharged from and aroundan electron emission device crashes against an electron, the gas emittedfrom the image forming material can be efficiently absorbed. Therefore,a local raise in pressure can be avoided. In addition, the sectionalshape of the arranged non-evaporation getter does not physically affectthe orbit of an electronic beam, and the influence on the orbit of theelectronic beam by charging of non-evaporation getter can be minimized.Furthermore, even if there is subtle positional discrepancy of thenon-evaporation getter, the influence on the orbit of the electronicbeam can be reduced.

Additionally, a getter has preferably an arc-shaped sectional form, sothat the projection on the surface of the getter can be reduced, therebymitigating the local concentration of the electric field on the surfaceof the getter.

Furthermore, in addition to the getter having an arc-shaped section, thewiring on which the getter is arranged also has preferably thearc-shaped section.

Thus, by having arch-shaped sections of the getter and the wiring, theprojection on the surfaces of the getter and the wiring can be reduced.Therefore, the local concentration of the electric field on the surfaceof the getter and the wiring can be reduced.

Furthermore, when the shapes of the sections are thus controlled, it isdesired that an available getter is a non-evaporation getter whichexcels in formability.

It is also desired that the width of the getter is smaller than thewidth of the wiring because a getter is formed after the wiring isformed, and the alignment precision of the getter should be easilyobtained.

In this example, a non-evaporation getter made of an alloy mainlycontaining Zr is arranged for the wiring for applying a voltage to drivean electron emission device of an electron source substrate, and thesection is arc-shaped. Such configuration will be described below.

The configuration is specifically explained below with reference to FIG.78. FIG. 78 a is a perspective view of a type of an example of theconfiguration of the image forming device to which the thirteenthconfiguration is applied. Reference numeral 661 denotes an electronsource substrate (also referred to as a rear plate), can be obtained byarranging a plurality of electron emission devices on an insulatingsubstrate such as a glass, etc., and is provided with the wiringdescribed later. Reference numeral 662 denotes an X direction wiring(lower wiring). Reference numeral 663 denotes a Y direction wiring(upper wiring). Reference numeral 664 denotes an electron emissiondevice, and is formed between device electrodes 665 and 666. Referencenumeral 667 denotes a non-evaporation getter arranged on the upperwiring. A metal back and a fluorescent object is arranged inside a faceplate 676.

The electron source substrate 661 is described in detail with referenceto FIG. 78 b. FIG. 78 b is a top view showing a type of the electronsource substrate shown in FIG. 78 a. An inter-layer insulating layer6688 is arranged between the X direction wiring 662 and the Y directionwiring 663 for insulation.

FIG. 79 a is a sectional view along A-A′ shown in FIG. 78 b. FIG. 79 bshows a characteristic of the orbit of an electron beam obtained when anaccelerating voltage is applied to the face plate 676 under theassumption that the electron emission device is driven as the Xdirection wiring 662 would be a relatively positive electrode. It isknown an electron emitted from an electron emission portion 669 of theelectron emission device 664 is attracted toward the X direction wiringwhich is applied a positive signal voltage, and draws a orbital curve asshown in FIG. 79 b. At this time, if the cross section of thenon-evaporating getter 667 has rectangular shape, then the orbital ofthe electron beam is interrupted by the edge of the getter, and electroncan not reach the face plate 676 so as not to emit light by afluorescent film 674. In addition, if the cross section of thenon-evaporating getter 667 has rectangular shape, then the distancebetween the orbital of the electron beam and the edge portion ofnon-evaporating getter 667 having positive potential become very short,and it electrically warps the orbital of the electron beam, and electroncan not reach the face plate 676 so that the fluorescent film 674 doesnot emit light. Furthermore, in the case an electron source substrate661 has a plurality of electron emission devices, all orbits of theelectron beam emitted from all devices have to be protected from beinginterfered by the non-evaporating getter 667. In the production process,if the non-evaporating getters 667 are simultaneously disposed, and ifthere arises a discrepancy in an arrangement position of any one ofnon-evaporating getters 667, then there arise discrepancies in thearrangement positions of all non-evaporating getters 667, and it isdifficult to achieve the production system with high precision.Therefore, if the cross section of the non-evaporating getter 667 isarch-shaped, then the yield rate of the production can be improved ascompared with a rectangular-shaped section.

A non-evaporating getter is disposed on the X direction wiring and the Ydirection wiring. The cross section of the non-evaporating getter isarch-shaped with a little round at the edge portion as shown in FIG. 79a. As a non-evaporating getter, a marketed Zr type alloy (for example,HS-405 powder (product of Japan Getters), St-707 (product of SAES), etc.can be applied, and the section become arch-shaped when the getter isdisposed.

Example 1

The image forming device according to this example has the configurationsimilar to that of the device which is shown in FIG. 78 a, and has anon-evaporating getter (NEG) disposed on the X direction wiring (lowerwiring) 662 and the Y direction wiring (upper wiring) 663 formed by theprinting method.

A metal mask having an opening to the shape of the upper and lowerwiring is prepared and sufficiently aligned, and then a film of aZr—V—Fe alloy is disposed by the sputtering method. The opening portionof the prepared mask has inversely tapered shape, and it makes possibleto obtain the arch-shaped section of the non-evaporating getterdisposed. The thickness of the non-evaporating getter 667 is adjusted tobe 50 μm. As described above, the electron source substrate 661 havingthe non-evaporating getter is disposed. The composition of thesputtering target used is Zr for 70%, V for 25%, and Fe for 5% (weightratio).

According to this example, the non-evaporating getter of 240 μm width isdisposed on the wiring of 280 μm width. On the point A on the surface ofthe getter having a tangent crossing one point of the electron emissionportion of electron emission devices closest to the getter, theintersections B and C between the circle having a radius of 2.4 μm (1%of the getter width) and the getter are obtained, and the inner anglemade by B-A-C is measured as 174 degrees. With the radius is 12 μm (5%of the getter width), the inner angle is 150 degrees. According to thisexample, the points B and C are the intersections between the section ofthe getter and the circle. However, when the layer of the getter isthin, and the points B and C do not cross the getter, the intersectionsbetween the tangent at the end of the getter and the circle having theabove mentioned radius are set as the points B and C, and the innerangle is obtained.

According to this example, the method of forming a non-evaporatinggetter is used with a metal mask. However, the present invention is notlimited to this application. That is, a combination of a patterningusing photolithography and oblique evaporation, a process of drawingwith an adhesive using a dispenser or printing process and to whichadhere the powder of a non-evaporating getter, and an electroplatingprocess, etc. can be used to obtain an arch-shaped section.

Example 2

A getter with a configuration shown in FIG. 79 a is produced in thefollowing procedure.

A metal mask having an opening in the shape of the upper wiring isprepared, correctly aligned, and provided with a film of a Zr—V—Fe alloyby the sputtering. The opening portion of the prepared mask is processedin an inversely tapered shape so that the cross section of the producednon-evaporating getter can be arch-shaped. The getter layer is 2 μmthick. The composition of the used sputtering target is 70% of Zr, 25%of V, and 5% of Fe (weight ratio).

Example 3

According to this example, the image forming device shown in FIG. 67 ais produced. The cross section of the getter according to this exampleis still arch-shaped as in the Example 2 of the 13th Configuration, andthe producing method is similar to that of the Example 2. The imageforming device according to this example has spacers. The wiring fordriving each electron emission device is obtained by arranging the upperwiring and the lower wiring in a matrix form. Then, the getters andspacers are arranged together on the upper wirings. A getter of the sameshape and same process as the getter arranged on the wiring is alsoarranged on the face plate side. The getters on the face plate side arearranged on the black materials to avoid color mixing betweenfluorescent films with various colors. On the other hand, the spacersalso touch the face plate, and the touching positions are set on theblack materials. The arrangement positions of the getters and thespacers are set such that the positions do not overlap each other on theface plate and the rear plate.

According to this example, a larger area image forming device can berealized by placing spacers. One reason why the getters are arranged onan area other than non-occupied area by the spacer is that, the area notoccupied by the getters becomes smaller by the spacers covering a partof the getter when a spacer is provided on the getter arranged on thewiring.

Furthermore, according to the present invention, the corner of thespacer is rounded as shown in FIG. 35. This is for preventing fromaccidental break due to the concentration of the electric field at thecorner, the stress concentration against the corner, etc.

By operating the image forming device according to this example with theabove mentioned structure, a good image is obtained with high brightnessfor a long period.

(14th Configuration)

FIG. 80 a shows a characteristic of wiring structure for the 14thConfiguration, and FIG. 80 b shows the cross sectional view along A-A′shown in FIG. 80 a. A lower wiring 1601 and an upper wiring 1603 areprovided in a way having a intersection with each other on a rear plate1600. The upper wiring 1603 is formed on an inter-layer insulating film1602, and is insulated from the lower wiring 1601.

The row (horizontal) direction wiring (upper wiring 1603) and the column(vertical) direction wiring (lower wiring 1601) provided on the electronsource substrate have the layer stacking structure through an insulatinglayer (inter-layer insulating film 1602) at the intersection portion. Ifthe vertical direction wiring (lower wiring 1601) and the horizontaldirection wiring (upper wiring 1603) do not have good surface shapes, itcan be possible that the convex portion arising on the lower wiringmakes a short circuit with the upper wiring by piercing through theinter-layer insulating film, and it cause an undesired electricdischarge arises between the face plate and the rear plate. Then, it isdesired that the surface shapes of the upper and lower wiring have asurface roughness expressed by Ra of 0.5 μm or less, a desired value of0.3 μm or less, and a more desired value of 0.2 μm or less, and theroughness Rz of 0.5 μm or less, a desired value of 3 μm or less, and amore desired value of 2 μm or less.

According to the study by the present inventors, the defect ofinter-layer insulation (short circuit between upper and lower wiring) atthe intersection portion between the lower wiring and the upper wiring,and the discharge phenomenon between the face plate and the rear platecan be possible to occur if there is a large projection on the surfaceof the wiring. However, it is practically impossible to check theexistence of a projection on all of several millions of intersections.Therefore, various checks are made to adopt the method of using anysubstitutional parameter, and it proves that the above mentionedproblems can be significantly reduced by an electrode satisfying theabove mentioned roughness of the surface. Ra is the average roughness ofthe center line indicating the roughness of the surface of an industrialproduct, and Rz is the parameter indicating the ten point averageroughness showing the roughness of the surface of an industrial product.

To satisfy the surface roughness, the particle size of a conductiveparticle used for a conductive paste is approximately 0.1 μm to 2 μm,and a more desired value of 0.3 μm to 1.0 μm. It is desired that aball-shaped particle is used.

Table 3 shows the paste used in this example. TABLE 3 Example 1 Example2 Example 3 Example 4 Shape of Ball Ball Ball Ball particle Ra (μm)0.292 0.268 0.198 0.177 Rz (μm) 2.854 2.571 1.916 1.884 Number of short1 1 0 0 circuits Example 5 Example 6 Example 7 Example 8 Shape of BallFlake Ball Ball particle Ra (μm) 0.161 0.355 0.467 0.367 Rz (μm) 1.8183.353 4.122 3.45 Number of short 0 3 5 4 circuits

The wiring is formed by the screen printing method. SX 300 mesh is usedas a screen printing. The emulsion is 15 μm thick, and is a product byTokyo Process Service. The pitch of the wiring in the vertical directionof the produced pattern is 230 μm, 720 lines with 110 μm width, and thepitch of the wiring in the horizontal direction is 690 μm, 480 lineswith 240 μm width. Then the product is baked at the temperature of 400to 520° C.

As an inter-layer insulating layer, NP-7730 paste of Noritake CompanyLimited is used, and the printing and baking processes are repeatedthree times. At the intersection portion between the wiring, the film isabout 16 to 20 μm thick. In the structure of the produced wiring, thenumber of intersections between wirings in the vertical and horizontaldirections are 345,600. The reliability of the insulating layer, thatis, the check of the short circuit between the upper and lower wiring isconfirmed by an original matrix checker, and scanned the allintersection points, and checked the existence of short circuit forabout 30 minutes. As shown on the table, in the case of Ra is 0.3 μm orless and Rz is 3 μm and less, there is few short circuits between theupper and lower wiring, in the case of Ra is 0.2 μm or less and Rz is 2μm and less, there is no short circuit, thereby it can be recognizedthat the reliability of the inter-layer insulation of the wiring isimproving.

On the other hand, a glass substrate is prepared, on which platinumdevice electrodes are disposed by photolithography method, apredetermined paste is used to form the vertical direction wiring, theinter-layer insulating layer, and the horizontal direction wiring inthis order. Ra of the vertical and horizontal direction wiring obtainedby said process is 0.211, and Rz is 2.286.

According to the configuration by controlling the roughness of thesurface of the wiring, the reliability of the wirings which driveelectron emission devices can be improved, that is, non short circuit isnot made between the upper and lower wiring so that the yield rate ofthe production without can be improved. In addition, an anode voltage(Va) can be raised to enhance the light intensity of a display panel.

(15th Configuration)

As an electron emission device provided on the electron sourcesubstrate, the configuration in which an electron emission portion isformed on a conductive thin film connected to a couple of paired deviceelectrodes, is preferably applied. The couple of device electrodes areconnected to the respective wiring, for example, one is connected to thecolumn direction wiring, and the other is connected to the row directionwiring. As such configuration of an electron source substrate, allelectron emission devices can be surrounded by the row direction wiringsand the column direction wirings. The amount of electrical charge on theelectron source substrate can be uniformed.

In this example, an area in which the row direction wiring is surroundedby a plurality of column direction wirings, and the column directionwiring is surrounded by a plurality of row direction wirings is definedas an intersection area.

The amount of electric charge of an electron source substrate can befurthermore uniform by making the width of at least one of the rowdirection wirings and the column direction wirings arranged on an areaother than the above mentioned intersection area wider than the width ofthe row direction wiring or the column direction wiring within the abovementioned intersection area.

In addition, as shown in FIGS. 98 and 99 described later, it isfurthermore desired to make the widths of both row and column directionwirings in an area other than the above mentioned intersection areawider than the width of the row or column direction wiring within theabove mentioned intersection area.

As shown in FIG. 81, electron sources in this configuration can beobtained by arranging a plurality of surface conductive electronemission devices and connecting them through the wirings in a matrixform (in this example, only nine unspecified electron sources areshown).

With this configuration, redundant row direction wiring X0, columndirection wiring Y0, and electrodes 1612 and 1613 are provided suchthat, in an electron emission device connected to the row directionwiring X1 and the column direction wiring Y1, the amount of electriccharge of the substrate exposure unit outside the device can be equal tothat of the electron emission device connected to the X2, X3, Y2, and Y3inside the device, and it is characteristic that all electron emissiondevices are surrounded by the row direction wirings and the columndirection wirings. In this example, it is desired that the electrodeconnected to a redundant wiring is not provided with a conductive thinfilm having an electron emission portion to avoid waste on an excessdevice current. Furthermore, it is desired that a redundant wiring Y0 isdesigned to be the same in shape as the wiring Y1, Y2, and Y3 such thatthe orbital of an electron emitted from adjacent electron emissiondevices can be the same as those of two other devices, thereby settingthe electric potential distribution around the devices in an uniformstate. Similarly, a redundant wiring X0 has also the same shape as thewiring X1, X2 and X3.

An example of the producing process of this configuration is describedbelow by referring to the attached drawings.

FIGS. 82 a through 82 f show the process of producing thisconfiguration. In the producing process, 3×3 electron sources, 9 intotal are provided for the substrate not shown in the figures in matrixform. In these figures, reference number 202 and 203 denote a couple ofdevice electrodes, reference number 204 denotes an electron emissionportion forming film, reference number 206 denotes a column directionwiring which is the first wiring layer, reference number 207 denotes arow direction wiring which is the second wiring layer, reference number208 denotes an inter-layer insulation film provided between the columndirection wiring 206 and the row direction wiring 207. Reference numeral209 denotes a window between the inter-layer insulation films 208 forconnecting the second wiring layer 207 with the device electrode 202.

First, a pattern of an device electrode material is printed using anoffset printing method on a substrate cleaned in advance, and is thenbaked, thereby forming the couples of device electrodes 202 and 203(FIG. 82 a). These device electrodes are provided for better ohmiccontact between the thin film of the electron emission portion and thewiring. Normally, since the thin film of the electron emission portionis much thinner than the wiring conductive layer, these deviceelectrodes are used to avoid the problems of wetting property, gapretainment, etc. As the method of forming device electrodes, it isuseful like that, vapor deposition, the sputtering method, the plasmaCVD method, etc., and the printing method using a thick film pastcontaining metal components and glass components as a catalyst. In thisexample, for a conductive thin film which form an electron emissionportion on an electrode, it is desired that the device electrode nearthe electron emission portion is thin to improve the step coverage of anelectrode edge. When a thick film printing method is used, an preferableavailable paste can be a MOD paste composed of an organic metalcompound. Obviously, other deposition method can be still useful, andany conductive material can be used as a component in the configuration.

The first wiring layer 206 featuring the present invention, the terminalportion (column end portion) of the first wiring layer 206 which is alower wiring, and the terminal portion (row end portion) of the secondwiring layer 207 which is the upper wiring, are simultaneously formed(FIG. 82 b). In forming the first wiring layer 206, the column directionwiring is provided with that connected to the device electrode 203 of anelectron emission device, and redundant wiring Y0 and redundantelectrodes 202′ and 203′ in an area (a column line of leftmost devices)on one side of which wiring is not formed. The redundant wiring is notlimited to one column, but there can be a plurality of columns.

Differing form the formation of the device electrode portion, a thickerfilm is advantageous because it reduces electric resistance. Especially,in an image forming device with a number of electron emission devices, athick film printing method using a thick film paste which produce arelatively thick film in a single layer is appropriate. It is obviousthat thin film wiring can be applied depending on the number of electronemission devices, density, etc. When the screen printing method is usedas a thick film printing method, it is possible that device electrodesconnected to the column wiring Y0 are formed under the above mentionedredundant column wiring Y0 in a form of a series of electrodes in alinear line.

Then, the inter-layer insulation film 208 is formed (FIG. 82 c). Theinter-layer insulation film 208 is formed at the intersection betweenthe column direction wiring and the row direction wiring. The componentsmaterial of the inter-layer insulation film 208 can be anything that canmaintains normal insulation, for example, a film of a thick film paste,etc. mainly containing an SiO₂ thin film, PbO not containing a metaldevice.

Then, the second wiring layer featuring the present invention is formed(FIG. 82 d). In forming the second wiring layer 207, the row directionwiring is provided with that connected to the device electrode 203 of anelectron emission device, and redundant wiring X0 and redundantelectrodes in an area (a column of uppermost devices) on one side ofwhich wiring is not formed. The redundant wiring is not limited to onerow, but there can be a plurality of rows. Furthermore, when an electronsource is driven in a method in which a scanning signal is sequentiallyapplied for each row in a surface conductive electron source group wiredin a matrix form by row and column as described later, at least theabove mentioned redundant wiring is connected to the wiring other thanthe adjacent wiring X1.

Then, the conductive electron emission portion forming film 204 isdisposed to connect the device electrode 202 with the device electrode203 (FIG. 82 e) and obtain the electron source substrate as shown inFIG. 82 f. The conductive film is disposed by the inkjet method of anorganic metal complex solution and baked. The ink jet method isdisclosed by, for example, Japanese Patent Laid-Open No. 8-273521, No.8-277294, No. 9-69334, etc.

In the above mentioned process, a pre-forming electron source substrateis produced (FIG. 177). FIG. 177 shows a row direction wiring terminalportion 205 a and a column direction wiring terminal portion 205 b, notshown in FIG. 82. Thus, the production can be realized at a lower costby forming each material on the electron source substrate in theprinting method.

The redundant wiring X0 with this configuration is connected to any oneof the above mentioned Dox1 through Doxm, and the redundant wiring Y0is, in one case connected to any one of the above mentioned Doy1 throughDoyn, and in another case connected to external terminals Dox0 and Doy0to fix the electrical potential.

Furthermore, as shown in FIG. 83, each electron emission device isarranged in an area sectioned by the wirings, the terminal portion ofthe X direction wiring is simultaneously printed and formed with the Ydirection wiring, and the insulation layer is provided at theintersection. Then, a wiring 162′ connecting every second wiring (X0 andX2 in FIG. 83) in the X direction wiring can be simultaneously formedwhen it is printed and formed in the X direction wiring. In this case,the wiring 162′ is insulated from the wiring X1 by an insulation layer161′.

As described above, the electrical potential prescription material suchas redundant electrodes 102′, 103′, or an terminal portion (drawingelectrode) for connection of each wiring to the drive circuit externalto the display device as shown in FIG. 83 are preferably arranged on thesubstrate surface outside the intersection area for prescribing theelectrical potential of the surface of the substrate.

Furthermore, the above mentioned potential prescribed material is morepreferably connected to each wiring, eliminating the necessity of apower supply dedicated to a potential definition member.

The examples with this configuration, etc. are described below.

Example 1

As the Example 1 of the present invention, an electron source isconfigured using the configuration of the electron source substrate asshown in FIG. 84 in which a number of flat surface conduction emissiondevices are arranged in a simple matrix form. According to this example,an electron source substrate 71 in which 120 devices 74 are arranged foreach line of a row direction wiring (X wiring) 72, and 80 devices 74 arearranged for each column direction wiring (Y wiring) 73 is used, therebyproducing an image forming device. Therefore, m in ‘Dxm’ is 80, and n in‘Dyn’ is 120. In FIG. 84, reference number 75 denotes a deviceelectrode.

FIG. 85 is a plan view of a part of the substrate on which a pluralityof electron emission devices 74 according to this example are arrangedin a matrix form, and FIG. 86 is a sectional view along A-A′ shown inFIG. 85 (an electron emission portion 75 is omitted in FIG. 86). FIGS.87 a through 87 g show the production process of the electron sourceaccording to this example. The units commonly appearing in these figuresare assigned the same reference numbers. In these figures, referencenumber 141 denotes an inter-layer insulation layer, reference number 142denotes a contact hole, reference numbers 52 and 53 denote deviceelectrodes, and reference number 54 denotes a conductive thin film. Eachprocess is described below.

Step-a:

On a substrate obtained by forming a silicon oxide film of 0.5 μm thickin the sputter method on a cleaned soda lime glass, Cr of 5 nm thick andAu of 600 nm thick are sequentially siapoaws in the vacuum vaporificmethod, and then a photo-resist (AZ 1370 of Hoechst) is applied byspinner method. After the baking process, a photo-mask image is exposedand developed to form a resist pattern of the lower wiring 72, and anAu/Cr disposed film is wet-etched to form the lower wiring 72 of adesired shape (FIG. 87 a).

Y0 is provided as redundant wiring featuring the present invention.

Step-b:

Then, the inter-layer insulation layer 141 of a 1.0 μm silicon oxidefilm is deposited in the RF sputtering method (FIG. 87 b).

Step-c:

A photo-resist pattern for forming the contact hole 142 is formed on thesilicon oxide film deposited in the above mentioned process b, and usingthis as a mask, the inter-layer insulation layer 141 is etched to formthe contact hole 142. The etching method is performed by the RIE(reactive ion etching) method using CF₄ and H₂ gas (FIG. 87 c).

Step-d:

Then, the device electrodes 52 and 53, and a pattern of gap between theelectrodes is formed using the photo-resist (RD-2000N-41 of HitachiChemicals), and the 5 nm thick Ti and the 100 nm thick Ni aresequentially disposed in the vacuum vapor deposition. The abovementioned photo-resist pattern is solved with an organic solvent, theNi/Ti disposed film is lifted off, and the device electrodes 52 and 53of 20 μm interval L of device electrodes and 300 μm width W are formed(FIG. 87 d).

Step-e:

After forming a photo-resist pattern for the upper wiring 73 as the Xdirection wiring on the device electrodes 52 and 53, Ti of 5 nm thickand Au of 500 nm thick are sequentially disposed in the vacuum vapordeposition method, an unnecessary portion is removed by the lifting-offprocess to form the upper wiring 73 in a desired shape (FIG. 87 e). Theredundant wiring X0 featuring the present invention is provided.

Step-f:

The Cr film of 100 nm thick is disposed and patterned in the vacuumvapor deposition method. On the film, an organic Pd solution (ccp 4230of Okuno Pharmacy) is applied by spinner, and a heating and bakingprocess is performed at 300° C. for 10 minutes. Thus, the formedconductive thin film 54 is 10 nm thick, and 5×10⁴Ω/Ø in sheet resistancevalue. Then, the Cr film and the baked conductive thin film 54 areetched with an oxide etchant to form a desired pattern (FIG. 87 f).

Step-g:

A resist pattern is formed at a portion other than the contact hole 142,and Ti of 5 nm thick and Au of 500 nm thick are sequentially disposed inthe vacuum vapor deposition method. The contact hole 142 is embedded byremoving an unnecessary portion by the lifting-off process (FIG. 87 g).

Next, an electron source is configured using the above mentionedpre-formed electron source. The process is described by referring toFIG. 84.

First, the lower wiring 72, the inter-layer insulation layer (not shownin the drawings), the upper wiring 73, the device electrode 75, and theconductive film 74 are formed on the substrate 71. As described above,an electron source substrate provided with a number of surfaceconductive electron emission device 74 is mounted in a vacuum container.

Step-h:

In the forming process according to this example, the vacuum systemshown in FIG. 88 is used. In a vacuum container 1405 whose pressure canbe reduced by a vacuum pump 1406, an electron source substrate in whichthe device electrodes 52 and 53, and the conductive thin film 54, andthe X and Y direction wiring are formed on the substrate 51 is mounted.The Y direction wiring is connected to a common electrode connected tothe ground, and a predetermined voltage pulse is applied from a powersupply 1401 to each X direction wiring (upper wiring). The flowingelectric current therefrom is measured by an ammeter 1410.

In this example, the pulse width of the voltage pulse applied to the Xdirection wiring (upper wiring) from the power supply 1401 is 1 msec,and 240 msec in pulse interval. A pulse of 1 msec in pulse width and 3.3msec in pulse interval is generated, and using a switching device, the Xdirection wiring for applying a voltage is switched to an adjacent line.

The pulse voltage height is 11V, the pulse waveform is a rectangularwave. In addition, in the forming process, the entire display panel ismaintained at 50° C., while pulse voltage is applied, mixed gas of H₂and N₂ is introduced.

In this forming process, a crack arises in a part of the conductive thinfilm 54 by a current (If) flowing through the conductive thin film 54.The crack portion can be electron emission portion 55 for emittingelectron.

In FIG. 88, reference number 1404 denotes an anode substrate oppositethe electron source substrate at a predetermined interval H, and avoltage is applied (an anode current Ie flows) at a predetermined timingfrom the power supply 1403 to the anode electrode of the anode substrate1404. The anode current is measured by the ammeter 1402.

Step-I:

Then an activating process is performed. benzonitrile is used as anorganic gas forming the atmosphere, a partial pressure is controlled at1×10⁻⁶ Torr, and the method of applying a pulse is the same as in theabove mentioned forming process. However, since a process cannot besimultaneously performed in all X direction wiring, 10X direction wiringlines are grouped as 1 block, 1 pulse is applied to 1 line, that is, 10applying operations are performed, thereby terminating an activatingprocess on 1 block. The process is sequentially performed on the otherblocks. The width of the pulse applied to the line is 1 msec, the pulseinterval is 10 msec, the pulse waveform is a rectangular wave, and thewave height value is 16 V.

Then, the entire substrate is maintained at 300° C., and then exhausted.When the pressure in the vacuum chamber is equal to or lower than 1×10⁻⁵Pa, the temperature drops to the room temperature, 1 KV is applied tothe anode electrode through a high voltage terminal, a drive pulse of15V is applied to each device, the amount of electron emission Ie andthe standard deviation σ of dispersion are measured on the deviceconnected to the target redundant wiring and to its adjacent wiring, andthe following results are obtained.

Comparative Example 1

Except that the above redundant wiring X0 and Y0 are not provided, theconstitution of this comparative example is identical to Example 1 andan electron beam source was made using the same procedure. TABLE 4Average Ie Average Ie in Y1 line σy1 in X1 line σx1 Example 1 1.8 μA 0.11.8 μA 0.1 Comparative 2.0 μA 0.4 2.1 μA 0.5 Example 1

From the above result, it is found that redundant wiring brought aboutan enhanced uniformity in electron emission quantity.

Examples 2 and 3

As Examples 2 and 3, an electron source with many plane typesurface-conduction emission devices arranged in a simple matrix as shownin FIG. 18 was formed using printed wiring and combined with an imageforming member to make up an image forming apparatus.

Referring to FIG. 89, the configuration and the production procedure ofthis example will be described below.

Examples 1 and 2 will be described.

FIGS. 89 a to 89 f are process drawings showing the production procedureof this example (here, a portion wired in matrix of 3×3, total 9, ofdevices situated at a corner of the image formation area as part ofelectron source on unillustrated substrate is shown). In FIGS. 89 a to89 f, Numerals 212 and 213, denote a pair of device electrodes, 214 aconductive film for the formation of an electron emission part, 216 afirst wiring layer, 217 a second layer and 218 an interlayer insulatingfilm provided between the first wiring layer 216 and the second wiringlayer 217. All the total devices are set in a configuration of 720devices arranged in row and 240 devices arranged in column.

First, on a previously washed substrate (here, a soda lime glasssubstrate is used), printing and baking of device electrodes isperformed to form a pair of electrodes 212 and 213 (FIG. 89 a). In thisexample, a thick-film print method was used as a method for forming afilm. The thick-film paste material used here is a MOD paste, the mainmetal ingredient of which is Au. In printing, the screen print methodwas used. After printing elements in a desired pattern, drying iscarried out at 70° C. for 10 min., then executing the burning. Thebaking temperature is 550° C. and the peak retention time is about 8min. The pattern after the print and burning was formed by setting onegroup of device electrodes 213 to 350×200 μm and another group of deviceelectrodes 212 to 500×150 μm. A pattern of sideways anisometric wasformed at a film thickness of about 0.3 μm and at intervals ofindividual electrodes 212 and 213 of 20 μm.

Next, a first wiring layer is formed (FIG. 89 b). In forming a firstwiring layer 216, Y-direction wires are formed in all patterns and thatin connection to device electrodes 213. In this example, a thick-filmscreen print method was used as the method for forming first wiringlayers 216. As paste materials, a mixture of fine-grained powder of aconductive material with a lead oxide-based glass binder was used. Inaddition as a conductive material Ag-paste was used. Besides, screenprint was performed in a desired pattern and then burned at 550° C. fora peak retention time of 15 min after the drying at 110° C. for 20 minto provide 100 μm wide and 12 μm thick Y-direction wires serving for afirst wiring layer 216. Herein, the first wiring layer 216characterizing the present invention is formed (FIG. 89 b). In additionto those formed in connection to electron emission device electrodes213, redundant wires Y0 and redundant electrodes 212′ and 213′ wereprovided adjacently to the left-end device column at which no wiring wasformed of end devices to one side as column wires in the formation of afirst wiring layer 216.

Furthermore, below the above redundant column wires Y0, those to theside of connection to the column wires Y0 among the above electrodedevices were linked and formed in the shape of a single continuous lineas shown in FIG. 89 a.

Here, an interlayer insulating film 218 was formed (FIG. 89 c).

This interlayer insulating layer 218 was formed at intersecting portionsbetween X-direction wires and Y-direction wires. As constituents of thisinterlayer insulating film 218, a PbO-based thick-film past containingno metallic component was used.

In the formation of an interlayer 218, a thick-film screen method wasused. Screen print was performed in a desired pattern and then burned at550° C. for a peak retention time of 15 min after the drying at 110° C.for 20 min to provide 500×500 μm sized and 30 μm thick interlayerinsulating layer 218.

Next, a second wiring layer 217 will be formed (FIG. 89 d). In theformation of a second wiring layer 217, the X-direction wires are formedin all patterns in contrast to a first wiring layer 216. The X-directionwires are formed in connection to respective device electrodes 212. Inthis wiring formation, a thick-film screen printing method was used asthe method for forming first wiring layers 216. The thick-film pastematerial used was the same Ag paste as with the first wiring layer 216and its metallic component is Ag. Screen print was performed in adesired pattern and then baked at 550° C. for a peak retention time of15 min after the drying at 110° C. for 20 min to provide 100 μm wide and12 μm thick X-direction wires serving for a second wiring layer 217 onthe first wiring layer 216. In this manner, with the formation of thesecond wiring layer, the matrix wiring comprising multiple (two) layersof the X-directional wiring and the Y-directional wiring insulated toeach other was completed (FIG. 89 d).

According to the above procedure, the portion of the matrix wiring wascompleted, but the paste material, print method and the like are notlimited to those mentioned here.

Finally, a thin conductive film 214 for the formation of an electronemission part (surface-conduction electron source) will be formed (FIG.89 e). In the formation of a thin conductive film 214, the liquiddroplet giving method described below was formed.

When liquid droplets are given onto device electrodes by a liquiddroplet giving device, a solution made of water, a metallic compound andan organic solvent and having a viscosity enough to make a droplet isused to basically form liquid droplets. In this example, Pd was used asthe metallic element of the metallic compound. As the liquid dropletgiving device, an ink-jet device or a bubble jet process device wasused. Burning was performed at 300° C. for 10 min, the dischargedquantity of liquid droplets was so regulated as to make a film ofthickness of 100 Å and a film indicating a sheet resistance of 4×10⁴ wasformed.

In FIGS. 89 a to 89 b, only the portion of 9 devices is illustrated, butsuch devices at a sequence of 720 in the X-direction and at a sequenceof 240 in the Y-direction were simultaneously formed to complete theconfiguration of an electron source board comprising multiple layers inthe simple matrix type.

Next, an electron source substrate with the surface-conduction electronsource produced as mentioned above was used to a display panel.Furthermore, redundant row wires X0 and redundant column wires Y0characterizing Example 2 are connected via out-of-vessel terminals Dx0and Dy0 to the ground to determine the electric potential.

Next, Example 3 will be described.

In this example as shown in FIG. 90, since as many redundant wires astwo are provided so as to reduce the influence of any printed wiredisconnection and the production procedure and the constituent memberwas set to the same as with Example 2 of 15th Configuration. However,except that electrodes below redundant wires were linked to provide alinear pattern. The redundant wires X0 and X0′ as well as Y0 and Y0′ areconnected in the vessel and are connected via the out-of-vesselterminals Dx0 and Dy0 to the ground to determine the electric potential.

Comparative Example 2

This comparative example is an image forming apparatus constructedwithout the provision of redundant wires in which the production processproceeded under the same conditions as with Example 2 of 15thConfiguration.

The results obtained in case of using the constructions of Examples 1, 2and the Comparative Example 2 are shown in Table 5. TABLE 5 Ie (Y1) σy1Ie (X1) σx1 Example 2 1.7 μA 0.1 1.7 μA 0.1 Example 3 1.6 μA 0.1 1.6 μA0.1 Comparative 1.9 μA 0.35 2.0 μA 0.4 Example 2 Luminance (Y1) σy1Luminance (X1) σx1 Example 2 4000 cd 150 4100 cd 160 Example 3 3900 cd130 3900 cd 145 Comparative 3700 cd 500 3800 cd 540 Example 2

As found from Table 5, the provision of redundant wires near devicespromotes the uniformity as an electron source and reduces the variationsof luminance. Here, a decrease in the average of luminance isattributable to a deformation in the form of an electron beam due to thepotential distribution, thus leading to an increase in the ratio ofelectron radiated to the black stripe of a face plate and a fall in theefficiency of conversion into light.

Example 4

In the above individual examples of 15th Configuration, redundant wireswere specified in potential via the out-of-vessel terminal, but thisexample is characterized in that row-direction redundant wires wereconnected to any one of the row wires connected to electron emissiondevices, here, to the second neighboring wire and column-directionredundant wires were connected to neighboring column wires. As shown inFIG. 91, an insulating layer 161 was formed at part of the row wireadjacent to the redundant row wire X0 and then the third wire 162 wasformed in the shape of connecting the redundant wire X0 to the secondneighboring row wire X2.

By adopting the above configuration, the provision of the aboveredundant wire eliminated the electron emission devices not sandwichedby wires and the charged state near a device became equivalent to allother devices, so that the following effects were obtained as electronsources corresponding to the above phenomenon:

(1) Enhancement in the uniformity of electron emission characteristics;

(2) Enhancement in the shape uniformity of electron beams;

(3) Reduction of time fluctuation in electron emission characteristicsand the shape of electron beams; and

(4) Reduction in charged quantity and eliminated deterioration ofelectron sources due to electric breakdown with an electrode or wiring.

In brief, in the image forming apparatus using electron sources asmentioned above, an increased uniformity of luminance and a higher imagecharacteristic was implemented.

(16th Configuration)

The construction of the wire lead part in a display panel can be takenas follows. In other words, this example provides a construction withthe length of the row-directional or column-direction lead wire partoptimized and the periphery of the image display section to be narrowedas much as possible. An example according to this construction will bementioned below.

Example 1

FIG. 92 is a plan view showing a part of a display panel (image displayapparatus) to which to apply this 16th Configuration. The display panelshown in FIG. 92 is a display panel using surface-conduction electronemission devices according to one aspect of 16th Configuration and apart of the panel prior to packaging a flexible cable is shown tospecifically describe the length of the lead wire part in FIG. 92.

In FIG. 92, Numeral 3001 denotes a device board of the image displayapparatus comprising surface-conduction emission devices androw-direction and column-direction wires formed by the print wiring,numeral 3002 denotes a face plate with fluorescent materials andpositive electrodes placed in a plane opposite the device board 3001,numeral 3003 denotes a pixel section with surface-conduction emissiondevices placed at intersections on the matrix wiring, numeral 3004denotes one-block lead wires at the column-direction side printed forbutting against a flexible cable (unillustrated) after dividing thecolumn-direction wires into blocks, numeral 3005 denotes one-block leadwires at the row-direction side printed for butting against a flexiblecable (unillustrated) after dividing the row-direction wires into blocksas with lead wire 3004, numeral 3006 denotes a getter member forabsorbing the gas released from the pixel section during the display ofimages and numeral 3007 denotes a frame used for the vacuum sealing ofthe face plate 3002 and the device board 3001.

Symbol L denotes the length of lead wiring evaluated in this example,while numeral 3011 denotes a distance to the getter 3006 placed inconsideration of creeping discharge from the pixel section 3003, numeral3012 denotes the width of a frame constructed for the vacuum sealing.The outline part of the frame becomes an outline of the face plate 3002.Numeral 3013 denotes the length of a flexible junction part for thedirect packaging with a flexible cable, numeral 3014 denotes thedistance from the outline part of the device board to the portion withprinted wiring, numeral 3015 denotes the length determined from theprinting angle at the time of print wiring on the device board, theone-block length 3017 obtained when dividing the lead wiring intomultiple blocks and the quantity of clearance 3016 between the blocks.

With this example, in optimizing the length of a lead wire, the lengthof a lead wire at the side of column direction wires and at the side ofrow direction wires was equated. This is because equating the width fromthe pixel section 3003 to the device board 3001 enables panelconstructing members and the like after the packaging of a flexiblecable to be constructed at one and the same specifications, thus leadingto saving the cost and the like. Thus, the length of a lead wire is tobe described at the side of column direction wires. Incidentally, thelength of a lead wire at the side of column direction wires and at theside of row direction wires is not limited to one and the same length,but individual length may be changed in light of the design of a panel.

Next, a manner of determining the length L of a lead wire will bedescribed in details. The length L of a lead wire is determined byfactors 3011 to 3017.

First, referring to 3011. Numeral 3011 denotes the distance from thepixel section 3003 to the getter part 3006 as mentioned above. Thegetter 3006 is a member for absorbing the gas released from the pixelsection during the display of images and absorbs the gas generated whenelectrons emitted from a surface conduction emission device collidesagainst a fluorescent material of the face plate 3002 in case of drivingthe display. Thereby, the panel interior is always kept constant invacuum degree (near 1×10⁻⁵ torr). The getter member is generally made ofmetallic material or the like and, for example, constructed in the formof a wire disposed on a lead wire on the device board 3001 and on thespace of the face plate 3002. A problem in disposing a metallic memberin the panel is the creeping discharge with a high-voltage (anodevoltage) applied to the face plate 3002. The creeping discharge is morelikely to occur the nearer the getter member comes to the pixel section3003 and depends upon a value of anode voltage. Thus, to avoid the creepdischarge at the lowermost, it is necessary to keep the getter 3006 at acertain-distance from the pixel section 3003.

In this example the value experimentally established is adopted for3011, keeping the getter 3006 at least 4 mm or more (anode voltage 12kV) from the pixel section 3003.

Secondly, 3012 is to be at issue. First, the frame 3007 used for thevacuum sealing of the face plate 3002 and the device board 3001 will bedescribed. The frame 3007 is provided to prevent the slow leak from theoutside (atmosphere) in favor of the vacuum degree in the panel and toprevent the deformation due to a thermal stress of the panel during theheat treatment such as baking in the panel manufacturing process. Forthe frame member, those of adhesive type are principally used. The slowleak is considered to originate in the interface between the face plate3002 and the adhesive and the frame part is found to need a width ofabout 3 mm to 10 mm in order to avoid the slow leak. Thus, in thisexample, the width 3012 of the frame 3007 was set to at least 5 mm orgreater in consideration of preventing the deformation due to a thermalstress.

Next, flexible joints 3013 with the flexible cable will be described.For flexible joints for the connection to an external display circuit asthe display device, the contact resistance with the flexible cablebecomes important. In particular, at the row direction wire side, sincemultiple surface-conduction emission devices are connected, currentflows at a value of several A. Thus, in case the deviation of thecontact position due to an alignment fault between a lead wire and theflexible cable leads to an unstable contact resistance or an elevatedvalue of contact resistance, a problem of disconnection or voltage dropat the contact part takes place, thereby resulting in the deteriorationof image quality or line defects. To eliminate these problems andpromote the reliability, a contact with the flexible cable is made usinga technique such as ACF (anisotropic conductive film) in this example.

Furthermore, in this example, a construction that can cope with theprocess using a probe or the like in the panel manufacturing step isprepared on the flexible junction 3013. Accordingly, when checking theneighboring short-circuit of both row and column direction wired, forexample at the end of manufacturing step in the shape of FIG. 2,measurement is performable by contact of a contact part needle such asprobe with any position on flexible joints. As mentioned above, flexiblejoints 3013 are set to 5 mm in length including the checking contactpart in another step in consideration of contact stability with theflexible cable. The length 3014 is related to the quantity of clearanceextending from the outline part of the device board to the printedwiring portion and determined by a printing device. In this example, thelength 3014 is set to 2 mm.

As mentioned above, the length 3015 is determined by the length 3017 ofa lead wire in one block, the quantity of clearance 3016 between theblocks. and the print angle θ in the print direction during the printwiring. To explain these specifically, FIGS. 93 a and 93 b will bereferred to.

FIG. 93 a is an enlarged view of part of the panel of FIG. 92 for thecolumn direction wire part and in particular shows a packaged flexiblecable in the portion of a column direction lead wire 3004. Besides, tobe understandable, a package drawing of the flexible cable is omittedand an enlarged view of the clearance part between 2 blocks of the leftlead wire is shown in FIG. 93 b. In FIGS. 93 a and 93 b, Numeral 3008denotes the flexible cable corresponding to one block of a lead wire,numeral 3018 denotes the total length in column of the pixel section,numeral 3019 denotes the total length in column of flexible joints, andnumeral 3110 denotes the one-side length of flexible joints when itslength 3019 exceeds the length of the pixel section 3018. Besides, 3111denotes the one-side unconfined length of a flexible cable 3008 at thepressure contact after registration with the alignment mark 3009 of alead wire. In this example, the unconfined quantity was set to 2.5 mm.Numeral 3112 represents the margin quantity of flexible cables at thepressure contact between them. This margin quantity is determined fromthe apparatus at the packaging of flexible cables to a certain degreeand required to be on the order of several mm. In this example, themargin quantity 3112 was set to 3 mm or longer. Usually, when joiningthe wiring by means of flexible cables, it is general to make the wiringpitch thinner in the flexible joints than in the pixel section andpromote the packaging density. Besides, because the total length 3019 offlexible joints is determined by flexible junctions and the clearance3016 of flexible cables between all individual blocks, 3019>3018 holdsfor a high precision apparatus such as XGA, whereas 3019<3018 holdsmostly for a relatively small number of pixels. In FIGS. 93 a and 93 b,joints in case of 3019>3018 are shown.

First in evaluating the quantity 3015, the quantities 3019 and 3018 mustbe calculated. The quantity 3019 can be calculated as follows.

On letting X and P be the number of wires in a one-block interval andthe wiring pitch, respectively, the pitch Bp in a one-block interval iscalculated asBp=X*P+16  (1).

The number Bn of all blocks on letting Dyn be the number of columndirection wires is calculated asBn=Dyn/X  (2).

In accordance with Formulae (1) and (2), the quantity 3019 is found asBn×Bp (number of blocks x inter-block pitch).

Besides, the quantity 3018 can be calculated as follows. From the pixelpitch Pn in the pixel section and the number Dyn of column directionalwires, the quantity 3018 is found as Pn×Dyn.

Next, based on the above calculation, the quantity 3110 will beevaluated. The quantity 3110 is found as 3110=3019−3018/2. Both ends ofthe flexible joints are not confined within the pixel section 3003 if3110 is positive, and is disposed within the pixel section 3003 if 3110is negative.

Usually, since the inter-block wiring pitch P is more minutely formedthan the pitch Pn in the pixel section, such construction as 3019 isnearly equal to or smaller than 3018 can be performed by increasing thelength 3017 of the flexible joint. In fact, on taking into considerationthe inter-pitch precision of flexible cables, the alignment accuracy offlexible cables at the pressure contact, problems of a pressure contactdevice and further the restriction of number of pins in a connector orthe like used when connecting a flexible cable to the display circuitsystem forces the length of 3017 to be actually restricted to a certainextent under present circumstances.

If an extremely positive or negative value of 3110 is obtained from theabove calculation, i.e. if the wiring pitch is set under conditions thatthe total length of the flexible joints differs greatly from the lengthof the pixel section 3003, it is preferred to calculate a optimal valueof 3015 by changing a value of clearance 3016 or changing the number Xof wires in one-block so that 3018 and 3019 approach to each other asclosely as possible.

Next, the quantity 3015 can be evaluated from the print angle θ in theprint direction during the print wiring and the above quantity 3110. Theprint angle θ is determined by the angle of the mesh used during theprint. When an attempt is made to print a wiring pattern with a greaterangle than the mesh angle, for example, disconnection of wires takesplace on account of a poor discharge from on the mesh or aninterference. In this example, the print angle is set to about 25degrees from the above conditions. From these, 3015 can be found fromthe following calculation:3015=3110/tan θ (θ=25 degrees)  (3).

In the formulae (1) to (3) mentioned above, the number X of wires inone-block of the flexible junction part and the quantity 3016 ofclearance between the blocks are dominant in (1) and the size of animage display apparatus and the number of pixels are dominant in (2), sothat optimal values of 3015 for varied specifications of individualimage display apparatus and lead wire parts were evaluated.

Incidentally, the value of 3015 is computed at the side of wiring incolumn here, but can be evaluated by a similar calculation also at theside of wiring in row. θ can be set below 45 degrees. TABLE 6 ImageDisplay Specifications Image display Number of devices Wiring pitchspecifications (column * row) (column * row) mm I8 (mm) 30″VGA 2556 *480 0.29 * 0.87 742 42″XGA 4068 * 768 0.23 * 0.69 932 60″HD  5760 * 10800.23 * 0.69 1324 1. 30″ VGA Specifications Number of In-Pixel Wires Dyn2560 In-Pixel Wiring Pitch Pn 0.29 Between Flexible 16 = 8 In-BlockWiring Pitch P 0.2 Print Angle θ = 25 Number of in- Inter-block Numberof all I10 block wires X pitch Bp (mm) blocks Bn I9 (mm) I8 (mm) (mm) I5(mm)  40 16 64 1024 742 141 302  80 24 32 768 742 13 28 160 40 16 640742 −51 −109 320 72 8 576 742 −83 −178 640 136 4 544 742 −99 −212Between Flexible 16 = 15 Number of in- Inter-block Number of all I10block wires X pitch Bp (mm) blocks Bn I9 (mm) I8 (mm) (mm) I5 (mm)  4023 64 1472 742 365 783  80 31 32 992 742 125 268 160 47 16 752 742 5 11320 79 8 632 742 −55 −118 640 143 4 572 742 −85 −182 2. 42″ XGASpecifications Number of In-Pixel Wires Dyn 4068 In-Pixel Wiring PitchPn 0.23 Between Flexible 16 = 8 In-Block Wiring Pitch P 0.2 Print Angleθ = 25 Number of in- Inter-block Number of all I10 block wires X pitchBp (mm) blocks Bn I9 (mm) I8 (mm) (mm) I5 (mm)  40 16 102 1672 932 348745  80 24 51 1220 932 144 309 160 40 25 1017 932 43 91 320 72 13 915932 −8 −18 640 136 6 864 932 −34 −72 Between Flexible 16 = 15 Number ofin- Inter-block Number of all I10 block wires X pitch Bp (mm) blocks BnI9 (mm) I8 (mm) (mm) I5 (mm)  40 23 102 2339 932 704 1509  80 31 51 1576932 322 691 160 47 25 1195 932 131 282 320 79 13 1004 932 36 78 640 1436 909 932 −12 −25

The above table shows the values of 3015 evaluated at values ofclearance 3016 between the flexible joints set to 8 mm and 15 mm forimage display sizes of 30, 42 and 60 inches. When actually determining3015 from the above table, for example, on referring to the 60″ HDspecifications, 3015 amounts to 30 mm at the clearance 3016 set to 8 mmand the number of inter-block wires set to 320, which is found to beminimized. In contrast, in case of 30″ VGA, 3015 amounts to 11 mm at theclearance 3016 set to 15 mm and the number of inter-block wires set to160, which is found to be minimized. As shown above, calculation wasperformed at varied numbers of inter-block wires in a flexible joint foreach image display size, thereby an optimal value of 3015 to be set.Incidentally, the number of wires in one block is not limited to theabove, but may be varied if necessary. Furthermore, a minus valueindicated by 3015 originates in the fact that the total length of aflexible joint becomes shorted than the total length of the imagesection 3003 and is not especially at issue in determining 3015.

Next, the added value of the creepage distance of insulation 3011 andthe frame width 3012 (for 11=4 mm and 12=5 mm, 11+12=9 mm) is comparedwith the determined value of 3015. In other words, for the optimal valueof 3015 found from the above individual tables, the creepage distance ofinsulation 3011 for the disposition of a getter 3006 and the width ofthe frame 3012 provided on the face plate 3002 are required at thelowest. Thus, in case of the value of 3015 equal to or less than 9 mm,i.e. in case of ‘3011+3012>3015’, a value of ‘3011+3012’ is employed inplace of 3015 and 3015 is taken as the value determining the L value ofa lead wire in case of ‘3011+3012<3015.

Besides, in case of ‘3011+3012>3015’, the frame of a width 3012 may beinstalled just near the creepage distance of insulation 3011. By addingthe above determined value of 3015 or ‘3011+3012’ to 3013 and 3014, thelength of a lead wire L is evaluated.

After all, in this example, an optimal value was shown for the lengthdistance L of a lead wire in case of construction from a getter 3006 anda frame 3007 in the face plate part. Thereby, implementing the panelaiming a narrowed frame of the image display panel became possible.

Example 2

FIG. 94 shows part of the display panel of Example 2 to which 16thConfiguration is applied. In FIG. 94, like symbols are attached to thosesimilar to constituents shown in FIG. 92.

Example 2 greatly differs from Example 1 of 16th Configuration in that agetter is formed on the matrix wires in the pixel section 3003 with thegetter member excluded. Like Example 1 using a nonevaporation gettermaterial, a getter in the matrix is used to adsorb the gas emitted fromthe pixel section at the time of displaying an image. In FIGS. 94, 3001,3002, 3003, 3004, 3005, 3007, 3012, 3013, 3014 and 3015 are omitted fromthe description because they are similar to those of the Example 1.Numeral 3011 denotes the distance therefrom when the pixel section 3003constitutes the frame 3007 of the face plate, which is a distance enoughto avoid the creep discharge with a high voltage (anode voltage) like3011 in FIG. 93. Here, 3011 was set to 4 mm. As with Example 1 of 16thConfiguration, the length L of a lead wire depends upon how to set avalue of wiring length 3015. As shown in Example 1 of 16thConfiguration, 3015 is determined by the length 3017 of a lead wire inone block, the clearance 3016 in one block and such others and allcomputing formulae for finding a lead wire may be the same as withExample 1. Besides, a value of 3015 may be determined on the basis ofthe table shown in Example 1. Furthermore, the angle θ of printed wiringmay be also the same as with Example 1.

Next, the added value of the creepage distance of insulation 3011 andthe frame width 3012 (11=4 mm and 12=5 mm, then 11+12=9 mm) will becompared with the determined 3015. To be specific, for the same reasonas with Example 1 of 16th Configuration as mentioned above, in case of‘3011+3012>3015’, a value of ‘3011+3012’ is determined in place of 3015and 3015 is taken as the value determining the value L of a lead wirelength in case of ‘3011+3012<3015. And, by adding the above determinedvalue of 3015 or ‘3011+3012’ to 3013 and 3014, the length of a lead wireL is evaluated. Besides, also in this example, a value of ‘3011+3012’ isrequired at the lowest in determining the length L of a lead wire.

After all, an optimal value was shown for the length distance L of alead wire in case of construction from a frame 3007 in the face platepart. Thereby, implementing the panel aiming a narrowed frame of theimage display panel became possible.

As described above, with 16th Configuration, the length of a lead wiringpart is enabled to be computable under several setup conditions indetermining the length of a lead wire for the display of an image by animage forming apparatus. Thus, also in the case of a large-sized displaypanel and of accompanying an increase in the number of wires, the panelcorresponding to a narrowed frame of the image forming apparatus can beimplemented. Besides, the weight-lightening of a panel can be achievedalso by implementing a narrowed frame.

(17th Configuration)

With respect to the lead part of wiring on an electron source substrate,the following construction can be further adopted. Namely, such aconstruction that the width of X-direction wires and Y-direction wireshas a more widely formed area outside the image forming area approachingthe relevant image forming area than within the above image forming area(Example 1 mentioned later) can be taken. Furthermore, a construction ofan area with the width of the above X-direction wires or Y-directionwires widely formed at outer four corners of an image forming areaapproaching the relevant image forming area can be also taken.

FIGS. 95 and 96 are schematic structural drawings (plan views) of anExample 1 of image forming apparatus according to 17th Configuration,using an electron source substrate with election emission devicesdisposed in a matrix. FIGS. 95 and 96 show the enlargement of theleft-end margin part of an image forming area and the top-end marginpart of an image forming area, respectively. Incidentally, in theseFIGS. 95 and 96, the right end of an image forming area and the bottomend of an image forming area are shaped symmetrically.

Numerals 3202 and 3203, 3206 and 3207, and 3208 denote an deviceelectrode, wiring and an inter-layer insulating film, respectively. Thewiring 3206 and 3207 are led out to outside the image forming area, i.e.to a position where no electron emission device is formed, respectivelyand are formed so as to become wider in this position. This aims toreduce the exposed area of the substrate surface outside the imageforming area, thereby making difficult the occurrence of charging inthis district.

FIG. 97 is a sectional view of an image forming apparatus with thewiring structure shown in FIGS. 95 and 96. In FIG. 97, Numerals 3231 and3232 denote a rear plate serving for the base body with an electronsource formed and a face plate with a fluorescent film 3233, a metalback 3234 and the like formed. The rear plate 3231 and the face plate3232 are supported by a frame 3235 at a fixed interval.

In Example 1, as mentioned above, the wiring 3206 and 3207 are led outto outside the image forming area, i.e. to a position where no electronemission device is formed, respectively and are formed so as to becomewider in this position. By such a construction, the exposed area of ahigh resistance surface outside the image forming area can be reducedand the disturbance of an image in the end of the image forming area canbe prevented.

FIGS. 98 to 100 are schematic structural drawings (plan views) ofExample 2 and show the enlargement of the top left end part among fourcorners of an image forming area, but the other three corners also havea similar shape. Incidentally, like symbols are attached to thosesimilar to constituents shown in FIGS. 96 and 97.

The wiring 3207 comprises m X-direction wires DX1, DX2, . . . DXm andthe wiring 3206 comprises n Y-direction wires DY1, DY2, . . . DYn. Inthis Example 2, these wiring 3206 and 3207 is widely deformed in theshape of DX1 and DY1 at the top left end corner as shown in FIG. 98.This aims to reduce the exposed area of the substrate surface at anouter corner part of the image forming area, thereby making difficultthe occurrence of charging in this district. Like this, DXm and DY1 atthe bottom left end (unillustrated), DX1 and DYn at the top right end(unillustrated) and DXm and DYn at the bottom right end are widelydeformed respectively, thereby reducing the exposed area of thesubstrate surface at outer corner parts of the image forming area.

Since it is object of Example 2 to reduce the exposed area of thesubstrate surface at outer corner parts of the image forming area, onlythe X-direction wires (DX1 at the top left end) may be widely deformedas shown in FIG. 99 or only the Y-direction wires (DY1 at the top leftend) may be widely deformed as shown in FIG. 100.

FIG. 101 is a schematic structural drawing (plan view) showing Example3, using an electron source substrate with electron emission devicesdisposed in the shape of a matrix. In FIG. 101, the top left end partamong the four corners of an image display area is shown in enlargeddimension, but the other three corners have a similar shape.Incidentally, Numerals in FIG. 101 denote parts similar to thosedesignated with like Numerals in FIGS. 98 to 100.

In FIG. 101, Numeral 3209 denotes a conductive member disposed at anoutside corner of the image forming area. The conductive member 3209 isdisposed to reduce the exposed area of the substrate surface at a cornerpart of the image forming area and can use the same material as with thewiring 3206 and 3207. Here, by connecting the conductive material toeither one of the wiring 3206 and 3207 so as to equate in potentialthereto, the electric potential can be specified.

Next, examples of 17th Configuration will be mentioned.

Example 1

The fundamental construction of an image forming apparatus according tothis example is similar to those of FIGS. 98 to 100. The width of thewiring 3206 and the mutual distance between the wiring 3206 are set toapprox. 70 μm within the image forming area and to approx. 220 μm.Besides, outside the image forming area, i.e. in the outside region ofdevice electrodes situated at the outermost end, the width of the wiring3206 was widened to 150 μm and the mutual distance between the wiring3206, i.e. the exposed width of the substrate surface is set to approx.140 μm. Incidentally, the wiring 3206 was formed to the end of the basebody so as to become a lead electrode as it is.

The width of the wiring 3207 and the mutual distance between the wiring3207 are set to approx. 280 μm within the image forming area and toapprox. 340 μm. Besides, outside the image forming area, i.e., in theoutside region of device electrodes situated at the outermost end, thewidth of the wiring 3207 was widened to 440 μm and the mutual distancebetween the wiring 3207, i.e., the exposed width of the substratesurface is set to approx. 180 μm. Incidentally, the wiring 3207 wasformed to the end of the base body so as to become a lead electrode asit is.

Example 2

In this example, wires 3206 are formed as with Example 1 of 17thConfiguration. Incidentally, here, out of wires 3206, DY1 and DYn areformed in a widened shape at outer four corners of the image formingarea so as to become similar to those of FIG. 98. Next, as with Example1, an inter-layer insulating layer 3208 is formed and further the upperwires 3207 are formed. Incidentally, here, out of wires 3207, DX1 andDXm were formed in a widened shape at outer four corners of the imageforming area so as to become similar to those of FIG. 98. Here, theywere formed so that the distance between DY1 and DX1 in a widely formedregion becomes approx. 200 μm or smaller.

In a display panel constructed thus, a high quality image, free of imagedisturbance and stable for a long time, was obtained at four cornerparts.

Example 3

In this example, the wiring is formed as with Example 2 of 17thConfiguration, but the wiring 3207 was formed like FIG. 99. Also on adisplay panel according to this example, a high quality image, free ofimage disturbance and stable for a long time, was obtained at fourcorner parts.

Example 4

In this example, the wiring is formed as with Example 2 of 17thConfiguration, but the wiring 3206 was formed like FIG. 100. Also on adisplay panel according to this example, a high quality image, free ofimage disturbance and stable for a long time, was obtained at fourcorner parts.

Example 5

An image forming apparatus according to this example is fundamentallycharacterized in that the wiring is constructed by the screen print likeFIGS. 97 and 101. One procedure of a method for manufacturing an imageforming apparatus according to this example is shown in FIGS. 102 a to102 d. Referring to FIG. 97, FIG. 100 and FIGS. 102 a to 102 d, afundamental construction method and a manufacturing method of an imageforming apparatus according to this example will be described below.

Step-a:

As with Example 1 of 17th Configuration, device electrodes 3202 and 3203are formed on a cleaned glass substrate (FIG. 102 a).

Step-b:

As with Example 1 of 17th Configuration, the wiring 3206 is formed.Here, a conductive member 3209 is simultaneously formed at a givenposition, i.e. at outer four corners of the image forming area (FIG. 102b). Incidentally, the distance between the conductive member 3209 andwires 3206 was set to approx. 200 μm or less.

Step-c:

Next, as with Example 1 of 17th Configuration, an inter-layer insulatinglayer 3208 is formed. Here, so that the conductive member 3209 is notconnected to the nearest upper wiring at the forming time of thesubsequent wiring, the inter-layer insulating layer 3208 is formed alsoon the conductive member 3209 (FIG. 102 c).

Step-d:

With Example 1 of 17th Configuration, the upper wiring 3207 is formed.Here, the conductive member 3209 is formed so as to be connected to thenearest next wiring 3207 (FIG. 102 d). Incidentally, the distancebetween the conductive member 3209 and the nearest next wiring of thewiring 3207 was set to approx. 200 μm or less.

By the above steps, there can be formed a substrate with the deviceelectrodes 3202 and 3203 connected in the form of a matrix by the wiring3206 and 3207.

Step-e:

At and after this step, the electric external lead was carried out inthe form of connecting the wiring through an anisotropic conductive film(ACF) as with Example 1 of 17th Configuration to manufacture an imageforming apparatus according to this example and display an image. As aresult, a good image can be stably displayed at a brightness (approx.150 fL) enough to be satisfied as a TV receiver for a long time and ahigh quality image free from image disturbance was obtained even at fourcorner parts.

According to this construction, charging on a high electric resistancesurface exposed to the surface of an electric source substrate can besuppressed to eliminate any influence on the orbit of electron emittedfrom electron emission devices, so that a large-screen planar-type imageforming apparatus, e.g. a color flat TV set, capable of retaining a goodimage for a long time can be implemented.

(18th Configuration)

Regarding a display part such as a fluorescent material layer, metalback and black matrix provided on the face plate, the thickness of animage display panel must be thinned to implement a thinner display panel(image display apparatus). In that case, the distance between the rearplate 4005 and the face plate 4000 shown in FIG. 18 must be reduced. Incase of such a construction, a considerably high electric field isgenerated between the rear plate 4005 and the face plate 4000. Here, themetal back 4006 is preferably a continuous film because of aiming toapply a high voltage Va to the entire fluorescent material film, preventthe charging of a fluorescent material and take out a ray emittedbackward (in a rear direction) from the fluorescent material to thefront by means of the mirror effect. Besides, since acceleratedelectrons have to excite a fluorescent material through the metal back4006, the metal back 4006 is preferably in the shape of a thin film.However, the fluorescent material is powdery and accordingly thefluorescent material film becomes porous, on the surface of which aconsiderable degree of ruggedness is present. Besides, on a black matrixprovided to prevent the color mixture of a fluorescent material,eliminate the color discrepancy even for a somewhat deviation of beampositions and further promote the contrast of an image by absorbing theouter light, a considerable degree of ruggedness is present like theabove fluorescent material film. For these reasons and also because nocontinuous film is formed by depositing a metal directly on thefluorescent material film, a filming step is employed generally as astep of manufacturing a metal back.

A construction of a metal back in contact with the face plate in whichtwo or more contact spots are present within limits of 20 μm×20 μm forany spot or the contact area occupies 50% or more can be adopted. Byadopting such a construction, since the contact part between the metalback and the face plate is present to a moderate extent even for ahigher electric field between the rear plate and the face plate of adisplay panel (an image forming apparatus) than 1 kV/mm, a force imposedon the contact part is reduced when a Coulomb attraction force acts andthe possibility of peeling off in the metal pack markedly decreases,thus leading to the excellency in durability and reliability.

Besides, by setting an arrangement that in any place of the above metalback, three spots or more of above contact parts are present withinlimits of 20 μm×20 μm or the contact area is 50% or more, a forceimposed on the contact part by the Coulomb attraction is further reducedand the possibility of peeling off in the metal pack markedly decreases,thus leading to the excellency in durability and reliability.

As mentioned above, the provision of a black matrix in the above faceplate makes it possible to absorb the outer light, promote the contrastand prevent the color mixture of a fluorescent material in theneighboring pixel. In addition to this, since the metal back is incontact with the black matrix, the metal back does not float in a wideextent. Thus, under action of the Coulomb attraction, a force imposed onthe contact parts between the metal back, a fluorescent material and theblack matrix can be reduced and the possibility of peeling off in themetal pack under action of the Coulomb force markedly decreases.

Besides, in a step of manufacturing a metal back, a large heightdifference between the fluorescent material film and the black matrixbrings about the accumulation of a great amount of a resin material in alower part of the fluorescent material or black matrix during thefilming process, thus making the film thicker. When an attempt is madeto remove the resin material by burning after manufacturing a metal filmthereon, the quantity of a gas generated by pyrolysis increases at thethick film portion and the floating of the metal back ends in occurring.To prevent this, here, letting tp (μm), tb (μm) and rp (μm) be theaverage thickness of a fluorescent material film in one pixel, theaverage thickness of the black matrix adjacent thereto and the averagegrain size of fluorescent materials, the average thickness tb is set astp−rp<tb<tp+rp. Thereby, the accumulation of a resin material at a lowerportion of the fluorescent material film or the black matrix disappearsand the possibility of peeling off in the metal pack under action of theCoulomb force lowers.

Besides, by caving the glass substrate in the fluorescent material-filmmaking region of the above face plate so as to fill this concave portionwith a fluorescent material and making a difference between the averageheight of the top surface of a fluorescent material film per pixel andthe average height of the black matrix adjacent thereto equal to or lessthan the average grain size of fluorescent materials, such a problembecomes unlikely to occur that a resin material is accumulated in thelower portion of the fluorescent material film and the black matrixduring the filming process, the film is thickened and the metal backfloats during the baking.

Furthermore, the face plate has a black matrix and may be so constructedthat a substance of other material than the metal back is stacked on theblack matrix and brought into contact with the metal back. According tothis construction, the metal back is in contact with the materialprovided on the black matrix, so that the metal back ends in no floatingin a wide extent. Thus, a force imposed during the action of the Coulombattraction on the contact parts between the metal back, a fluorescentmaterial and the black matrix is reduced and accordingly the possibilityof peeling off in the metal pack under action of the Coulomb attractionmarkedly decreases.

Besides, when the film with a metal film manufactured is in contact onthe bulk or a screen comprising particles of a very small grain size ina step of manufacturing a metal back, a gas generated by the pyrolysisduring the baking is hardly degassed and the floating of the metal backbecomes likely to occur. Besides, by contraries, when the film with ametal film manufactured is in contact on a screen comprising particlesof a very large grain size, the contact portion between the metal backand the face plate becomes very small after the baking for a highflatness of the film and the metal back becomes likely to peel off. Suchbeing the case, on letting rz (μm) and rp (μm) be the average grain sizeof a material stacked on the above black matrix and the average grainsize of a fluorescent material, the relation rp÷2<rz<3rp÷2 is set up.Thereby, the floating of the metal back becomes unlikely to occur duringthe baking and the contact portion between the metal back and the faceplate does not decrease, so that the metal back becomes unlikely to peeloff under action of the Coulomb attraction.

Besides, by making the diffusive reflectance of the material stacked onthe above black matrix greater than 70%, a ray emitted from afluorescent material is not absorbed by the material on the black matrixand can be taken out efficiently forward. As a result, the brightness ofthe image forming apparatus is elevated.

Besides, by setting the material stacked on the above black matrix tothe above fluorescent material, a metal back having the contact portionat a great ratio as the essence to the present invention becomes easierto manufacture and further the step of manufacturing a faceplate issimplified, thereby enabling the production cost to be saved.

Besides, on the above face plate, three colors of fluorescent materialsare painted separately to display a color image, where by making one ofthe fluorescent materials stacked on the above black matrix occupy 80%or more, a metal back having the contact portion at a great ratio as theessence to the present invention becomes easier to manufacture andfurther the step of manufacturing a face plate is simplified, therebyenabling the production cost to be saved.

Besides, on the above face plate, three colors of fluorescent materialsare painted separately to display a color image, where by choosing thefluorescent materials stacked on the above black matrix to be twoadjacent colors of fluorescent materials, a metal back having thecontact portion at a great ratio as the essence to the present inventionbecomes easier to manufacture and further the step of manufacturing aface plate is simplified, thereby enabling the production cost to besaved.

Besides, by setting the ratio of areas in the black matrix occupied bytwo colors of fluorescent materials stacked on the above black matrix to(4˜6):(6˜4), a metal back having the contact portion at a great ratio asthe essence to the present invention becomes easier to manufacture andfurther the step of manufacturing a face plate is simplified, therebyenabling the production cost to be saved.

Besides, by setting the ratio of areas in the black matrix occupied bytwo colors of fluorescent materials stacked on the above black matrix to(9.5˜6):(0.5˜4), a metal back having the contact portion at a greatratio as the essence to the present invention becomes easier tomanufacture and further the step of manufacturing a face plate issimplified, thereby enabling the production cost to be saved.

Besides, the glass substrate in the black matrix manufacturing region ofthe above face plate is concave, where by filling this concave portionwith a material of black matrix to make a difference between the averageheight of the top surface of a fluorescent material film per pixel andthe average height of the black matrix adjacent thereto equal to or lessthan the average grain size of fluorescent materials, a metal backhaving the contact portion at a great ratio as the essence to thepresent invention becomes easier to manufacture.

Besides, when the convexo-concave difference of the metal back is great,the surface area of the metal back for one site of contact increases andthe Coulomb attraction applied to the contact part increases.Accordingly, the convexo-concave, difference of the metal back withinlimits of 20 μm×20 μm is made equal to or less than the average grainsize of fluorescent materials. Thereby, on application of the Coulombattraction to the metal back, the force imposed on the contact portiondecreases and the possibility of peeling off for the metal backdecreases.

Hereinafter, examples of this Configuration will be referred to.

Example 1

Referring to FIGS. 103, 104 a to 104 d, and 107 a and 107 b, theconstruction of a face plate and a metal backing as subject of 18thConfiguration will be described.

After washing/drying a 2.8 mm thick soda lime glass (base 1300), using ablack pigment paste containing a glass paste and a black pigment apattern comprising 240 longitudinal stripes, 100 μm in width and 290 μmin pitch, and 720 transverse stripes, 300 μm in width and 650 μm inpitch was produced commonly at a thickness of 20 μm by the screen printmethod as shown in FIG. 107 a to make a black matrix 1301 (FIG. 104 a).In this example, a black matrix was produced by the screen print method,but needless to say, the production method is not limited this and byway of example, the photolithography method may be used for production;nevertheless, use of the screen method is preferable in view of a thickfilm and cost-saving. Besides, as the material of a black matrix, ablack pigment paste containing a glass paste and a black pigment wasused, but needless to say, the material is not limited to this andcarbon black, for example, may be used. Here, under circumstances ofproduction by the screen printing and in view of as thick a film as 20μm, the above black pigment paste was used. Besides, in this example,the black matrix was produced in the shape of a matrix as shown in FIG.107 a, but needless to say, is not limited to this and a stripe-shapedarray, a delta-shaped array or other arrays may be adopted.

Next, as shown in FIG. 107 a, three colors of fluorescent materials areapplied at the opening of the black matrix 1301 at three times for eachone color by using red, blue and green fluorescent material pastes 1302(FIG. 104 b). In this example, a fluorescent material film was made upusing the screen printing, but needless to say, is not limited to thismethod and may be made by the photo lithography, by way of example.Besides, fluorescent materials are chosen to be P22 fluorescentmaterials used in the field of CRT, comprising red color (P22-RE3;Y202S: Eu3+), blue color (P22-B2; ZnS:Ag, Al) and green color (P22-GN4;ZnS:Cu, Al) and 7 μm of median diameter Dmed in average grain size, butneedless to say, are not limited to this and other fluorescent materialsmay be used. Besides, a fluorescent material film was made up so as tobecome 20 μm in mean (FIG. 104 c). Here, if the thickness is notsufficiently flattened, an nonwoven fabric with isopropyl alcohol (IPA)absorbed may be provided on a sufficiently flat planar glass to increasethe flatness by pressurizing the fluorescent material film and the blackmatrix on the face plate through aids thereof. Then, by baking thissubstrate at 450° C. for 4 hr, the resin component in the paste waspyrolyzed and removed to obtain a face plate of a diagonal screen sizeof 10 inches and a aspect ration of 4:3, comprising 720×240 dots. Here,on measuring the thickness of the fluorescent material film and theblack matrix by using a touch-needle type surface roughometer, nogreater difference between the average thickness of the fluorescentmaterial film per pixel and the average thickness of the black matrixadjacent thereto than 7 μm, average grain size of fluorescent materials,was observed anywhere.

Next, a method for fabricating a metal backing on this face plate willbe described.

With the face plate prepared as mentioned above placed on a spin coater,a solution of colloidal silica dissolved in pure water was applied on asubstrate while rotating to wet the convexo-concave portion of thefluorescent material film. Subsequently, a solution of polymethacrylatedissolved in toluene was applied by a spray on the substrate whilerotating so as to uniquely adhere on the whole surface and dried byblowing a warm wind to the substrate to make a resin film on thefluorescent material film and the black matrix, thereby flattening thesurface. Here, as a step of flattening, the solution of polymethacrylatedissolved in toluene was applied after the wetting the fluorescentmaterial film, but needless to say, another solvent type lacquer liquidmay be used or a step of applying and drying an acryl emulsion to thefluorescent material film, by way of example, may be also carried out asanother method. Thereafter, on the flattened face plate, a 1000 Å thickAluminum film was made by the vacuum deposition. And, this face platewas conveyed into a baking furnace and heated to 450° C. to remove theresin film by pyrolysis.

The contact portion of the metal backing 1303 obtained thus (FIG. 104 d)of the face plate with the fluorescent material film and the blackmatrix was observed under a scanning electron microscope (SEM). At thistime, because of being difficult to observe on observation at ahigh-acceleration voltage at this time, a 1000 Å thick metal backing wasobserved at an acceleration voltage of 2 kV. On observing the metalbacking under SEM, the metal backing at a contact portion is shapedalong the fluorescent material film or the black matrix and the abovecontact portion can be well observed. By SEM observation, the number ofcontact portions within limits of 20 μm×20 μm and their contact areawere measured. Measurement from the selected black matrix opening wasmade at 8 sites of the black matrix opening adjacent thereto and at anextent surrounded by them and such a measuring process proceeded at 10sites randomly sampled from the whole face plate. The obtained result isshown in Table 7. As a result of measurement, it was observed that therewas no case where the number of contact portions of the metal backingwithin limits of 20 μm×20 μm was less than two and the metal backing wasin good contact with the face plate.

Furthermore, with the above face plate fixed a given gap apart oppositea sufficiently large electrode than the face plate in the vacuumchamber, a high DC voltage was applied to the metal back and graduallyraised, the voltage at the start of discharge was measured and thecorresponding electric field strength (hereinafter, referred to asdischarge start electric field strength) was evaluated. Incidentally,here, the electric field strength is defined as the voltage, applied tothe metal backing, divided by the gap distance between the rear plateand the face plate. As a result of measurement, the discharge startelectric field strength was 7.7 kV/mm (the result is shown in Table 7).In this manner, a face plate with a metal backing well contacting couldbe obtained, thereby enabling the reliability of an image formingapparatus to be promoted.

Incidentally, by taking the black matrix 1301 as an example in FIG. 107a, a description was made, but the mask material is not limited to thisconstruction. For example, in conformity to the delta-shaped array of afluorescent material, such a pattern as shown in FIG. 107 b may beadopted. Besides, its opening may be set to such a circular opening asshown in FIG. 107 b.

Example 2

Referring to FIGS. 106 a to 106 d, 107 a and 107 b, Example 2 accordingto 18th Configuration will be described.

After washing/drying a 2.8 mm thick soda lime glass (substrate 1300)similar to that of Example 1 of 18th Configuration, a 3 μm thick blackmatrix 1301 was prepared as with Example 1 (FIG. 106 a). Next, by usingthree colors of fluorescent materials at the opening of the black matrix1301 as with Example 1, a 20 μm thick fluorescent material film was madein such an arrangement as shown in FIG. 107 a. Here, even if fluorescentmaterials are stacked on the black matrix to a larger or smaller extent,no color mixture occurs because the black matrix absorbs light.

Next, a step of having a stacked matter provided to reduce theruggedness of the face plate will be described. Since any ruggedness ofthe face plate allows the metal back likely to float, the ruggednessmust be reduced. The principal objective of this stacked matter is toincrease the contact portion of the metal backing for a decrease in suchruggedness. Besides, if the surface of the stacked matter is too smoothin the step of having a stacked matter provided, the close adherence ofthe black matrix and the metal backing remains possible to grow poorafter the baking of a film in a filming step, whereas the contactportion of the metal back decreases and the metal backing is possible tomake no continuous film if too rugged. Thus, the average grain size ofthe material to be used for a stacked matter is preferably taken intoconsideration. Besides, since the light emitted from a fluorescentmaterial are absorbed and the efficiency of light taken out forwardlowers if the stacked matter is absorbent of light, the diffusivereflectance of the above material is preferably 70% or greater.

In consideration of the above reasons, this example used magnesium oxidepowder, 4 μm in average grain size. This was dispersed into a resinbinder to make a magnesium oxide paste, a 20 μm thick film was producedon a glass substrate and its reflectance was measured to show as good avalue as about 85%. In this example, magnesium oxide powder, 4 μm inaverage grain size, was used as a material of the above stacked matter,but needless to say, this construction is not limited to this and anymaterial, say, boron nitride, may be used if only satisfies requirementsas mentioned above. Using the above mentioned magnesium oxide paste, astacked matter 1304 was prepared on the black matrix by the screenprinting (FIG. 106 c). In this example, the above stacked matter wasprepared by the screen printing, but needless to say, the preparingmethod is not limited to this and it may be prepared by thephotolithography, by way of example. Here, as with Example 1 of 18thConfiguration, an nonwoven fabric with isopropyl alcohol (IPA) absorbedmay be provided on a sufficiently flat planar glass to increase theflatness also by pressurizing the fluorescent material film and theblack matrix on the face plate through aids thereof if the thickness ofa stacked matter and a fluorescent material is not sufficientlyflattened. Subsequently, by baking this substrate at 450° C. for 4 hr,the resin component was pyrolyzed and removed to obtain a face plate. Onmeasuring the thickness/surface roughness of the prepared face plate byusing a touch-needle type surface roughometer, no greater differencebetween the average thickness of the fluorescent material film per pixeland the average thickness of the black matrix adjacent thereto than 7μm, average grain size of fluorescent materials, was observed anywhere.

Next, on the face plate, a metal backing 1303 was fabricated by the samemethod as with Example 1 of 18th Configuration to obtain the finishedface plate (FIG. 107D).

The face plate prepared thus was observed under SEM as with Example 1 of18th Configuration to measure the number of contact portions and thecontact area within limits of 20 μm×20 μm. The result is shown in Table7. As a result of measurement, it was observed that there was no casewhere the number of contact portions of the metal backing within limitsof 20 μm×20 μm was less than two and the metal backing was in goodcontact with the face plate. Besides, the discharge start electric fieldstrength was measured as with Example 1, which measurement provided avalue of 7.3 kV/mm.

Using the above face plate and a rear plate provided with a multipleelectron beam source similar to that used in Example 1 of 18thConfiguration, an image forming apparatus was manufactured, thusenabling the durability and the reliability of the image formingapparatus to be promoted. Besides, by promoting the utility efficiencyof light with a stacked matter of magnesium oxide provided on the blackmatrix, the luminance of the image forming apparatus was elevated on theorder of 10%.

Incidentally, the black matrix 1301 may be made up also in a patternhaving a circular opening as shown in FIG. 107 b.

Example 3

Next, referring to FIGS. 108 a to 108 d, 107 a and 107 b, Example 3according to 18th Configuration will be described.

After washing/drying a 2.8 mm thick soda lime glass (substrate 1300)similar to that of Example 1 of 18th Configuration, a 3 μm thick blackmatrix 1301 was prepared as with Example 1 (FIG. 108 a). Next, atricolor fluorescent material film was produced at the opening of theblack matrix in such an array as shown in FIG. 107 a. Producing afluorescent material film is performed by the screen printing and thatseparately for each color out of three colors of fluorescent materialsat three times. Here, the film made of first and second colors offluorescent materials (fluorescent material film 1302 a) was produced aswith Example 1 (FIG. 108 b). A third color of fluorescent material(fluorescent material film 1302 b) was stacked also on the black matrixin such a manner as to reduce the ruggedness of the face plate. Here, aswith Example 1 of 18th Configuration, an nonwoven fabric with isopropylalcohol (IPA) absorbed may be provided on a sufficiently flat planarglass to increase the flatness also by pressurizing the fluorescentmaterial film and the black matrix on the face plate through aidsthereof if the thickness of a fluorescent material is not sufficientlyflattened.

Subsequently, by baking this substrate at 450° C. for 4 hr, the resincomponent was pyrolyzed and removed to obtain a face plate. On measuringthe thickness/surface roughness of the face plate obtained thus by usinga touch-needle type surface roughometer, no greater difference betweenthe average thickness of the fluorescent material film per pixel and theaverage thickness of the black matrix adjacent thereto than 7 μm,average grain size of fluorescent materials, was observed anywhere.Besides, this face plate was observed under SEM, which observationrevealed that the last printed fluorescent material occupying 80% ormore of the whole surface area was present on the black matrix.

Next, on the face plate, a metal backing 1303 was fabricated by the samemethod as with Example 1 of 18th Configuration described above to obtainthe finished face plate (FIG. 108 d).

The face plate prepared thus was observed under SEM as with Example 1 of18th Configuration to measure the number of contact portions and thecontact area within limits of 20 μm×20 μm. The result is shown in Table7. As a result of measurement, it was observed that there was no casewhere the number of contact portions of the metal backing within limitsof 20 μm×20 μm was less than two and the metal backing was in goodcontact with the face plate. Besides, the discharge start electric fieldstrength was measured as with Example 1, which measurement provided avalue of 6.5 kV/mm.

Using the above face plate and a rear plate provided with a multipleelectron beam source similar to that used in Example 1 of 18thConfiguration, an image forming apparatus was manufactured, thusenabling the durability and the reliability of the image formingapparatus to be promoted.

Incidentally, the black matrix 1301 may be made up also in a patternhaving a circular opening as shown in FIG. 107 b.

Example 4

Next, referring to FIGS. 105 a to 105 d, 107 a and 107 b, Example 4according to 18th Configuration will be described.

After washing/drying a 2.8 mm thick soda lime glass (substrate 1300)similar to that of Example 1 of 18th Configuration, a 3 μm thick blackmatrix 1301 was prepared as with Example 1 (FIG. 105 a).

Next, a tricolor fluorescent material film was produced at the openingof the black matrix 1301 in such an array as shown in FIG. 107 a.Producing a fluorescent material film is performed by the screenprinting and that separately for each color out of three colors offluorescent materials at three times. Besides, a fluorescent material isprinted not in a pattern comprising dots printed at positions ofindividual opening of the black matrix but so as to make longitudinalstripes as shown in FIG. 107 a. First, a first color of fluorescentmaterial 1302 a was printed so as to allow each printed stripe to bulgeto its adjacent longitudinal stripes of the black matrix (longitudinalpattern of the black matrix) to about a half (FIG. 106 b). Subsequently,a second color of fluorescent material 1302 c was printed so as allowedto overlie on the portion to which the first color of fluorescentmaterial 1302 a was applied out of the adjacent longitudinal stripes andto bulge to another longitudinal stripe to about a half (FIG. 106 c).Subsequently, a third color of fluorescent material 1302 b was printedso as allowed to overlie on the adjacent longitudinal stripes (FIG. 106d). Here, as with Example 1 of 18th Configuration, an nonwoven fabricwith isopropyl alcohol (IPA) absorbed may be provided on a sufficientlyflat planar glass to increase the flatness also by pressurizing thefluorescent material film on the face plate through aids thereof if thethickness of a stacked matter is not sufficiently flattened.

Then, by baking this substrate at 450° C. for 4 hr, the resin componentwas pyrolyzed and removed to obtain a face plate. On measuring thethickness/surface roughness of the prepared face plate by using atouch-needle type surface roughometer, no greater difference between theaverage thickness of the fluorescent material film per pixel and theaverage thickness of the black matrix adjacent thereto than 7 μm,average grain size of fluorescent materials, was observed anywhere.Besides, this face plate was observed under microscope, whichobservation revealed that the top surface of the black matrix wascovered with both adjacent pixel fluorescent materials.

Next, on the face plate, a metal backing 1303 was fabricated by the samemethod as with Example 1 of 18th Configuration to obtain the finishedface plate (FIG. 105 e).

The face plate prepared thus was observed under SEM as with the Example1 of 18th Configuration to measure the number of contact portions andthe contact area within limits of 20 μm×20 μm. The result is shown inTable 7. As a result of measurement, it was observed that there was nocase where the number of contact portions of the metal backing withinlimits of 20 μm×20 μm was less than two and the metal backing was ingood contact with the faceplate. Besides, the discharge start electricfield strength was measured as with Example 1, which measurementprovided a value of 6.7 kV/mm.

Using the above face plate and a rear plate provided with a multipleelectron beam source similar to that used in Example 1 of 18thConfiguration, an image forming apparatus was manufactured, thusenabling the durability and the reliability of the image formingapparatus to be promoted. TABLE 7 Example 1 Example 2 Example 3 Example4 Number of contacts, 5 4 2 3 Min. (points/20 μm × 20 μm) Number ofcontacts, 11.4 10.2 6.8 8.3 Average (points/20 μm × 20 μm) Ratio ofcontact area (%) 55 39 19 25 Discharge start electric- 7.7 7.3 6.5 6.7field strength (kV/mm)

Incidentally, the black matrix 1301 may be made up also in a patternhaving a circular opening as shown in FIG. 107 b.

(19th Configuration)

For joining of a face plate, a frame member and a rear plateconstituting the vacuum vessel section in a display panel, athermoplastic polymer adhesive containing a polyphenyl compound can beused. Hereinafter, examples of 19th Configuration will be enumerated.

Example 1

FIGS. 109 a and 109 b are a perspective view showing the schematicconfiguration of a display panel according to the Examples 1 of 19thConfiguration and a sectional view taken on line C-C′ of FIG. 109 a. InFIG. 109, reference numeral 5001 denotes an electron source, comprisingmultiple electron emission devices disposed on a substrate and wiredappropriately, 5002, a rear plate, 5003, an outer frame, 5004, a faceplate, and 5009, 5014, adhesives, respectively. Reference numeral 5010denotes a row selective terminal, 5011, a signal input terminal, 5102,an upper wiring, 5103, a lower wiring and 5104, an insulating film,respectively.

As shown in the C-C′ sectional view of FIG. 109 b, the rear plate 5002and the face plate 5004 are joined via thermoplastic polymer adhesives5009 and 5014 containing a polyphenyl compound at their joints with theouter frame 5003. Inside the face plate 5004, the metal backing and thefluorescent material film 5007 are disposed and further the interior iscoated with a metal backing.

Adhesion using adhesives proceeded as follows: after molding andinstalling the polyether ketone-based sheet-shaped thermoplastic polymeradhesives 5009 and 5014 (Techno-Alpha, Ltd.; Product Name: Stay-Stick451) into the shape of an outer frame, soften the adhesives in an inertgas such as Ar by 350° C. heating treatment to perform the pressurecontact (0.3 kg/cm²) and then harden the adhesives intemperature-lowering process to fulfill the adhesion. Fixing the innerstructures such as an electron source 5001 was also performed similarly.Besides, in disposing a rear plate 5002 and a face plate 5004, aring-shaped getter 5016 of Ba-based evaporation type getter wassimultaneously disposed outside the image display area.

Incidentally, as polyphenyl compounds to be contained in the adhesives,polybisphenol A, carbonate, polysulfone, polyether ketone and the likeare mentioned.

Example 2

This example used polysulfone-based sheet-shaped thermoplastic polymeradhesives 5009 and 5014 (Techno-Alpha, Ltd.; Product Name: Stay-Stick415) as adhesives in the Example 1 of 19th Configuration and set theheating treatment temperature to 300° C. In these points, this examplediffers from Example 1.

Example 3

This example used polyether-based sheet-shaped thermoplastic polymeradhesives 5009 and 5014 (Techno-Alpha, Ltd.; Product Name: Stay-Stick401) as adhesives in the Example 1 of 19th Configuration and set theheating treatment temperature to 250° C. In these points, this examplediffers from Example 1.

Example 4

This example used polysulfone-based pasty thermoplastic polymeradhesives 5009 and 5014 (Techno-Alpha, Ltd.; Product Name: Stay-Stick301) as adhesives in Example 1 of 19th Configuration to apply coating toa glass member in an arbitrary shape by the dispenser coating method,performed the defoaming, volatilized the solvent at 150° C. andthereafter treated the joints at a heating treatment temperature of 300°C. In these points, this example differs from Example 1.

Use of polyphenyl compound contained adhesives to joints of members forthe forming of an enclosure like these allowed the adhesion process tobe accomplished by one step of adhesion at a heating treatmenttemperature of 350° C. or lower and therefore makes it possible toprovide a vacuum enclosure principally for an image forming apparatus,low in electric power cost.

(20th Configuration)

In joining for the formation of an enclosure, the joint part can beformed of two types of adhesives. For example, by use of a materialfunctioning to principally sealing the enclosure and a materialfunctioning to adhere, joints can be adhesively formed. In suchobjectives, a seal material provided with sealing function for jointscan be selected from materials made of metals such as In, Al, Cu, Au,Ag, Pt, Ti and Ni or their alloys and organic or inorganic adhesiveswhose surface coated with metals such as In, Al, Cu, Au, Ag, Pt, Ti andNi or their alloys, while adhesives having the adhesive function includean organic adhesive such as a thermoplastic polymer adhesive comprisinga polyphenyl compound or a polybenz imidazole resin-based adhesive orpolyimide resin-based adhesive and an inorganic adhesive based onalumina, silica, zirconia, carbon or the like.

In as sealing materials and inorganic adhesives based on zirconia andsilica as adhesives are mentioned to be the most preferable. When usingIn wire as sealing materials, an In wire is molded in an arbitraryshape, softened by heating at 160° C. or higher and brought intopressure contact to seal a joint during the temperature falling process,then an alumina-based pasty adhesive is applied to and around thesealing material by using a dispenser or the like, the moisture isevaporated at 100° C. or lower and adhesion is made on the order of 150°C., which procedure can satisfy the following conditions (1) to (6). Thejoining material using an inorganic adhesive based on In and alumina ispreferred especially in that the maximum thermal treatment temperatureis low, as compared with other joints.

Besides, as sealing materials, an inorganic pasty adhesive based onzirconia and silica is molded by using a dispenser or the like in anarbitrary shape to form a coating film made of in on the surface of aninorganic adhesive with the moisture vaporized at 100° C. or lower by apublicly-known vacuum deposition such as EB or sputtering, then In issoftened by heating at 160° C. or higher, an alumina-based pastyadhesive is applied to and around the sealing material by using adispenser or the like after the pressure contact and the sealing duringthe temperature-falling process, the moisture is evaporated at 100° C.or lower and adhesion is made on the order of 150° C., which procedurecan satisfy the following conditions (1) to (6).

(1) Thermal Resistance: in the vacuum baking (high-vacuum formation)process;

(2) Sealing property: high vacuum (minimized vacuum leakage andminimized gas transmittance) maintainable (however, only for sites inneed of vacuum maintenance);

(3) Adhesiveness: with a glass member;

(4) Released Gas Characteristics: low pressure released gas (high degreevacuum maintenance) characteristics;

(5) Thermal Treatment Temperature: its maximum is lower than about 400°C. of the frit adhesion (sealing) process; and

(6) Moldability: Conformable to an arbitrary frame shape and notfluidized near the adhesion temperature.

Furthermore, as a sealing material, Al is usable and organicthermoplastic polymer polyether ketone-based adhesives can be used asadhesives. Al as a sealing material and an organic polyetherketone-based thermoplastic polymer adhesives are molded in an arbitraryshape, the adhesive is softened by heating to 330° C. or higher and thenis hardened in the temperature-falling process for the fulfillment ofadhesion after the pressure contact and the sealing, thereby enablingthe conditions (1) to (6) to be satisfied.

Since joints using at least two members of a sealing material having theabove sealing function and adhesives having adhesive function are formedin the adhesion process at a maximum thermal treatment temperature of400° C. or lower, a vacuum enclosure principally for an image formingapparatus hardly related to luminance drop and life shortage, furtherhigh in display grade and abundant in getter effect can be provided at alow power cost.

Besides, to promote the close adhesion between joints and a glasssubstrate, it is effective to vacuum deposit a metal or alloy similar tothe sealing material on the joint surface in advance or to coat acoating agent containing a similar metal or alloy by a publicly-knowncoating method such as screen printing, dipping, spray or dispenser inadvance.

Examples of 20th Configuration will be described below.

Example 1

FIG. 110 a is a perspective view showing the general configuration of adisplay panel according to Example 1 of 20th Configuration and FIG. 110b is a sectional view taken on line C-C′ of FIG. 110 a. Except that thestructure of connection of an outer frame to a face plate and a rearplate is different, other configurations of this example are similar tothose shown in FIGS. 109 a and 109 b and like symbols are attached tolike constituents.

In FIG. 110, reference numeral 5214 denotes a sealing material and 5209,an adhesive, by both of them an outer frame 5003 is joined to a rearplate 5002 and a face plate 5004 at the respective joints.

In joining, In wires were employed as a sealing material 5214, molded inan arbitrary shape and softened by heating to 160° C. or higher, jointswere sealed in the temperature-falling process after the pressurecontact, then a pasty adhesive (Three Bond, Ltd.; Product Name: 3715)based on zirconia and silica was applied to and around the sealingmaterial in the shape of an outer frame and adhesion was performed onthe order of 150° C. after the moisture was vaporized at 100° C. orlower. The fixation of an internal structure such as electron source5001 is performed similarly. Besides, when installing a rear plate 5002and a face plate 5004, a Ba-based ring-shaped getter 5016 of aevaporation-type getter was simultaneously installed outside the imagedisplay area.

Example 2

As a sealing material for joints, use was made of a product obtainedfrom the molding of an inorganic pasty adhesive (Three Bond, Ltd.;Product Name: 3715) based on zirconia and silica by using a dispenser orthe like in an arbitrary shape and formation of a coating film 5015 bythe publicly-known vacuum deposition such as EB or sputtering on thesurface of the inorganic adhesive whose moisture was vaporized at 100°C. or lower. Next, by heating the sealing material at 160° C. or higher,the coating film 5015 made of in was softened to perform the pressurecontact and joints were sealed in the temperature-falling process, thena pasty adhesive (Three Bond, Ltd.; Product Name: 3715) based onzirconia and silica was applied to and around the sealing material 5214in the shape of an outer frame and adhesion was performed on the orderof 150° C. after the moisture was vaporized at 100° C. or lower.

Example 3

Except that at contacting portions of the rear plate 5002 and the faceplate 5004 with the sealing material of the outer frame 5003, In wasdeposited by a publicly-known vacuum deposition such as EB or sputteringand the following joints were used in place of the joints of Example 1of 20th Configuration, this example was carried out like the process ofExample 1. Namely, for joints of this example, Al as a sealing materialand polyether ketone-based thermoplastic polymer organic adhesives asadhesives were employed. Al of a sealing material and sheet-shapedorganic polyether ketone-based thermoplastic polymer adhesives weremolded in an arbitrary shape, the adhesives were softened by heating to330° C. or higher to perform the pressure contact and the sealing andhardened in the temperature-falling process to fulfill the adhesion.Also by this approach, the above conditions (1) to (6) can be satisfied.

Example 4

Except that the following joints were used in place of the joints ofExample 1 of 20th Configuration, this example was carried out like theprocess of Example 1. Namely, for joints of this example, In as asealing material and polysulfone-based thermoplastic polymer pastyadhesives (Techno-Alpha, Ltd.; Product Name: Stay Stick 301) asadhesives are employed. In wires are adopted as a sealing material 5214,molded in an arbitrary shape, softened by heating to 160° C. or higherto perform the pressure contact and the sealing in thetemperature-falling process, a polysulfone-based thermoplastic polymerpasty adhesive (Techno-Alpha, Ltd.; Product Name: Stay Stick 301)employed as adhesives 5209 is coated on a glass member in an arbitraryshape by using a dispenser and defoamed to vaporize the solvent at 150°C., then is heated to 300° C. and higher to perform the pressurecontact, adhesion is fulfilled by hardening the adhesive in thetemperature-falling process and this approach also can satisfy the aboveconditions (1) to (6).

(21th Configuration)

Usually, the metal backing provided on a face plate is so provided as tocover many fluorescent material layers neighboring through the blackmatrix and a relatively narrow gap between the face plate and the rearplate caused a problem the metal backing was pulled to the side of therear plate and peeled off under certain configurations or drivingconditions of a display panel. Accordingly, in this configuration, sucha problem is avoided by the provision of transparent electrodes at theoutside portion of a face plate.

FIG. 111 is a perspective view of a display panel according to thisconfiguration, where part of the panel is cut away to show the internalstructure. In FIG. 111, symbols similar to those of FIG. 27 are attachedto individual constituents.

Formed of a rear plate 1015, a side wall 1016 and a face plate 1017, isa hermetic vessel for maintaining the interior of the panel in vacuum.In fabricating a hermetic vessel, the sealing is necessary to allow thejoints of individual members to retain a sufficient strength andair-tightness, while the sealing was achieved, for example, by coatingfrit glass to joints and baking them at 400 to 500° C. for 10 minutes orlonger in the atmosphere or in the atmosphere of nitrogen. Besides,since the interior of the above hermetic vessel is retained in vacuum onthe order of 10⁻⁶ Torr., a spacer 1020 is provided as the atmosphericpressure structure to prevent the fracture of a hermetic vessel due tothe atmospheric pressure or an expected shock. On the underside of theface plate 1017, a fluorescent material film 1018 is formed. Since thisexample is a color display apparatus, portions of the fluorescentmaterial film 1018 are distinctively coated with fluorescent materialsof three primary colors comprising red (R), green (G) and blue (B) usedin the field of CRT technology. The fluorescent material of each coloris distinctively applied in the shape of stripes, for example, as shownin FIG. 112 a, and a black conductor 1010′ is provided between therespective fluorescent material stripes.

Incidentally, in this example, the average thickness of each colorfluorescent material (luminous member) and that of the black conductor(black member or non-luminous member) are set to 20 μm and to 6 μm,respectively.

Black conductors 1010′ are provided in order to assure that there occurno shift in the display colors even if there is a slight deviation inthe position irradiated with electron beams, to eliminate a decline indisplay contrast by preventing the reflection of external light, and toprevent a fluorescent material film to be charged up by electron beams.Though graphite is mainly used to make a black conductor 1010′, but anyother material may be used in so far as suited to the objectivesmentioned above. Besides, the distinctive application of the fluorescentmaterials of the three primary colors is not limited to thestripe-shaped array shown in FIG. 112 a, but a delta-shaped array, forexample, as shown in FIG. 112 b or a grid-shaped array, for example, asshown in FIG. 114 is available.

Incidentally, the sectional shape of a face plate is typically shown inFIG. 175. Like this, the respective fluorescent materials of individualcolors, luminous member, differ in average thickness from the blackconductor 1010′, non-luminous member.

Incidentally, in case of manufacturing a monochromatic display panel, amonochromatic fluorescent material has only to be used for thefluorescent material film 1018 and the black conductor does notnecessarily need using.

Besides, on the rear plate side surface of a fluorescent material film1018, a metal backing 1019 publicly known in the field of CRT technologyis provided. The metal backing 1019 has as its objectives an improvementin the utilization factor by reflecting a part of the light emitted fromthe fluorescent material film 1018, a protection of the fluorescentmaterial film 1018 against damages due to bombardment by negative ions,an action as an electrode for applying an electron beam accelerationvoltage and an action as a conduction path for electrons that haveexcited the fluorescent material film 1018. A method for producing ametal backing 1019 comprises forming a fluorescent material film 1018 onthe face plate substrate 1017, then smoothing the surface of thefluorescent material film and vacuum depositing aluminum on thissurface. Incidentally, any other material than Al may be available if ithas the above functions.

On the top surface of the face plate (atmosphere side surface), as shownin FIG. 114, a transparent electrode 1022 made of ITO is provided, atleast, in the existent region of the metal backing. This transparentelectrode 1022 is connected to the ground. Thereby, even if a highervoltage than several kV (i.e., high field above 2 kV/mm) is appliedbetween the multi-beam electron source and the metal back 1019 on theface plate 1017, no metal backing is peeled off and the break downdischarge during the display of an image is prevented because theCoulomb force from the transparent electrode 1022 at the topside of theface plate acts on the metal backing, so that a good display image canbe obtained.

Besides, in an image display apparatus using a display panel as shown inFIGS. 111 and 115, electrons are emitted by applying a scanning signaland a modulation signal respectively from unillustrated signal generatormeans through out-of-vessel terminals Dx1 to Dxm and Dy1 to Dyn toindividual cold cathode devices (surface-conduction emission device)1012, the emitted election beams are accelerated by applying a highvoltage to the metal backing 1019 through a high-voltage terminal Hv tomake electrons collide with the fluorescent material film 1018 andindividual fluorescent materials (R, G and B) are excited so as toirradiate the respective colors of light, thereby resulting in thedisplay of a color image. The applied voltage Vf to between the wires1013 and 1014 was set to 14 [V] and the applied voltage Va to thehigh-voltage terminal Hv was set to 10 [kV].

Among display panels having no ground connection as mentioned above onthe surface of a face plate, there were some case where the metalbacking was peeled off under conditions of application voltages Va of 8[kV] to 10 [kV] on the high-voltage terminal Hv at a distance of 2 mmbetween the face plate and the rear plate.

Like this, according to 21th Configuration, the objectives of the metalbacking comprising a prevention of the potential drop, its action as theacceleration electrode, an improvement in luminance by a mirrorreflection of the light emitted from the fluorescent material film 1018and a protection of the fluorescent material film against damages due tobombardment by negative ions can be well attained. Furthermore, sincethe surface of the face plate is connected to the ground via atransparent electrode, the metal backing was prevented from being peeledoff from the face plate.

Besides, especially by exposing a transparent conductive material on theutmost surface of the face plate, unnecessary charging can besuppressed. As such a transparent conductive material, film-shapedtransparent electrode can be used. To this transparent conductivematerial, a potential enough to prevent unnecessary charging has only togiven, but a configuration of connecting the transparent conductivematerial to the ground as shown in FIG. 114 is quite preferable.

(22th Configuration)

As a configuration related to a lead wire from the face plate to the ahigh-voltage electron source, use can be made of the followingconfiguration. This configuration will be described using FIGS. 116 to119. FIG. 116 is an exploded perspective view typically showing oneexample of configuration of an image forming apparatus according to 22thConfiguration. FIG. 117 is a partly sectional view showing a section ofan anode terminal part viewed from the direction of the arrowhead A inFIG. 116. FIGS. 118 a to 118 e are process drawings typically showingthe preparing procedure of a rear plate substrate and show a part of theelectron source region. FIG. 119 is a plan view showing the periphery ofthe anode terminal part of the rear plate.

Reference numeral 7001 denotes a rear plate also used as a substrate onwhich an electron source is formed, reference numeral 7002 denotes anelectron source area provided with multiple electron emission devicessuch as electric-field emission devices and surface-conduction, wired toconnect the devices so as to be driven according to purposes, ledthrough a driving wire lead parts 7031 and 7032 to outside the imageforming apparatus for driving the electron source and connected to thedriver circuit (not shown). Reference numeral 7011 denotes a face platewith an image forming member formed, 7012, an image forming membercomprising fluorescent materials for giving forth light by the collisionof electrons emitted from the electron source area 7002, 7100, leadwires consisting of Ag or the like led for supplying a voltage to theimage forming member 7012 and 7004, an outer frame to be held betweenthe rear plate 7001 and the face plate 7011, while the electron sourcedriving lead part 7003 is a joint between the outer frame 7004 and therear plate 7001, embedded in a low-melting-point glass (frit glass 201)and led outward. For materials of a rear plate 7001, a face plate 7011and an outer frame 7004, soda lime glass, soda lime glass with a SiO₂coat formed on the surface, glass with a reduced content of Na, quartzglass or the like is used according to the conditions. Reference numeral7101 denotes a lead-in wire for leading in the voltage supplied from anexternal high-voltage electron source and 7102, an insulating memberwith an lead wire 7101 previously subjected to the airtight sealtreatment by use of a wax material such as Ag—Cu or Au—Ni and integrallyformed at the center of a pillar shape. For materials of an insulatingmember 7102, materials such as ceramics containing alumina or the likeand glass with a low content of Na, near in thermal expansioncoefficient to the material of a rear plate 1 and insulating against ahigh voltage are employed. Thereby, cracking between the insulatingmember 7102 and the rear plate 7001 due to thermal expansion differenceis prevented at high temperatures. Incidentally, any such otherconfiguration than a high-voltage terminal may be available and thepresent invention is not limited to this configuration. Besides, toassure the connection between a lead-in wire 7101 and lead wires 7100, aconnection member such as Ag paste or mechanical spring configurationmay be disposed for the configuration. Reference numeral 7104 denotes ahole, penetrating the air-tight lead-in terminal 7103, formed in therear plate 7001. Between the air-tight lead-in terminal 7103 and thethrough hole 7104 formed in the rear plate 7001, an adhesive member suchas frit glass 7201 having the air-tight capability is used to fix theterminal. Incidentally, the through holes 7104 are formed at fourcorners of the rear plate 7001 at which no lead-in wire 7031 or 7032 isformed and insides the outer frame 7004. Furthermore, as countermeasuresagainst discharge during the application of a high voltage of several kVthrough a lead-in wire 7101, such a configuration can be implemented byforming guard wires 7105 outside the driving lead wires 7031 and 7032that any discharge occurring inside is guarded by guard wires 7105 andthe devices are protected against damages such as deterioration due tothe flow of the discharge current through the driving lead wires 7031and 7032 to the electron source area. However, the creepage distance ofinsulation from the guard wires 7105 to the lead-in wires 7101 should betaken to be equal to or larger than 1 mm. This is because an extremeapproach to the guard wires will increase the occurring frequency of adischarge.

Reference numeral 7005 denotes an exhaust hole for the evacuation and7006, a glass tube disposed at the position corresponding to the exhausthole 7005 and connected to an unillustrated outer vacuum forming devicefor sealing the electron emission devices after the completion ofevacuation in the forming process. Incidentally, if a method forfabricating an image forming apparatus is adopted in a vacuum facility,the above glass tube 7006 and exhaust 7005 becomes unnecessary.

Next, referring to FIG. 118, one example of a method for manufacturing amultiple electron beam source according to 22th Configuration will bedescribed.

First, a conductive film made of a metal material is formed onwell-washed substrate and its pattern is finely machined by thelithography to form many pairs of device electrodes 221 and 222 (FIG.118 a). Next, column direction wires 224 are formed (FIG. 118 b) andfurther an interlayer insulating film 224 with notches 224 c is formed(FIG. 118 c). Subsequently, row direction wires 225 are formed (FIG. 118d) and finally a conductive film 226 is formed (FIG. 118 e).

Hereinafter, examples of 22th Configuration will be enumerated.

Example 1

Example 1 to which 21th Configuration is applied will be described.

On part of a face plate 7011 made of a soda lime glass material with animage forming member 7012 loaded, printed lead wires 7100 made of an Agmaterial led from one corner of the image forming member 7012 is formed.The formed position of this lead wire 7100 is set to a position capableof butting against the lead wire of a high-voltage terminal to be leadin from the through hole formed on the rear plate 7001. A lead wire 7100ensures the electric conduction by such a printed formation as to lie onthe image forming member 7012. Besides, the image forming member 7012comprises stripe-shaped fluorescent materials, black stripes and metalbacking, while fluorescent materials and black stripes are formed byprinting, on which an Al film was formed as metal backing by vacuumdeposition.

Between the rear plate 1 and the face plate 11, an outer frame 7004 madeof a soda lime glass material is retained. The driving wire lead parts7031 and 7032 are embedded in the LS 3081 frit glass 201 made by NipponDenki Glass at the joint between the outer frame 7004 and the rear plate7001. The lead-in wire 7101, formed of 426 alloy material, is brazed inadvance with Ag—Cu and subjected to vacuum air-tight seal treatment tointegrally form an insulating member 7102 made of alumina ceramic at thecenter of a pillar shape. The through hole 7104 is provided for leadingin the insulating member 102 integrally air-tight-formed with thelead-in wire 7101, whose disposing position will be described below.

As shown in FIGS. 116 and 119, the rear plate 7001 has places where nowire is formed at four corners alone, in one of which guard wires 7105are placed at the outermost of the driving wire lead parts 7031 and7032, and a through hole 7104 is provided 7 mm apart from the guardwires 7105. Such a configuration is made that the lead-in wires 7100 ofthe face plate 7011 is positioned opposite this through hole 7104. Inits assembling, a careful alignment is made so that unillustratedfluorescent materials of the image forming member 7012 of the face plate7011 and electron emission devices of the rear plate 7001 correspond toeach other. Besides, under circumstances that the air-tight lead-interminal 7103 and the glass tube 7006 were installed and the abovealignment was completed, this assembly is thrown into a heating furnacenot shown and a temperature of 420° C. is given to melt the frit glass7201 installed at the butt contact position of the face plate 7011, therear plate 7001 and the outer frame 7004. Then, cooling is allowed toproceed and the assemblage ends. In this condition, the face plate 7011,the rear plate 7001, the outer frame 7004, the glass tube 7006 and theair-tight lead-in terminal 7103 could be formed into a panel that can beconstructed air-tight. Thereafter, with the panel connected to anunillustrated vacuum exhauster via a glass tube 7006, its interior isexhausted and individual conductive films 226 (fine particle films) aresubjected to the energization forming and activation treatment.Subsequently, the exhaustion of the panel interior continues and thebaking treatment is performed to remove the organic molecules remainingin the vacuum panel. Finally, the glass tube 7006 is heated, moltentogether and sealed. In the above process, the vacuum panel is finished.

Next, to connect the driving wire lead parts 7031 and 7032 to thedriving board and the guard wires 7105 to an external ground terminal,an electric connection and a fixation of FPC (flexible printing circuit)7401 is accomplished at such a position as shown in FIG. 119 by using anexternal FPC packaging device. Thereafter, incorporating the vacuumpanel into a casing, connecting an electric board and the FPC and thelike are performed to finish an image forming apparatus. At this time,the wiring guide of the lead-in wire 7101 of the air-tight lead-interminal 7103 and the high-voltage power source can be packaged smoothlywithout interference with the FPC 7401 because of leading from a cornerof the back face of the vacuum panel.

In the above image forming apparatus, on supplying a high voltage to animage driving circuit and inputting an external picture to display animage, it was confirmed that a stable image display was performable fora long time without any influence of a breakdown discharge or the like.

According to this configuration,

(1) Cabling (wiring guide) of a high-voltage terminal at the casingmodularization of a vacuum panel is easily performable. When an electricboard for the driving is disposed at the back side of a vacuum panel, acontrivance of spacing in view of a discharge prevention is necessary inthe layout of a high voltage cable, but its disposition at a cornerfacilitates the assurance of spacing and can promote the degree offreedom in the design.

(2) Since in constructing an MTX wiring on the rear plate, a symmetricaldesign becomes possible, a design is easy to make and the MTX wiring isconvenient to a device for the configuration also.

(3) Since no driving wire is absent at a corner and guard wires areprovided, this configuration is advantageous also for a discharge.

An image forming apparatus which has these advantages has beensuccessfully provided.

Example 2

Referring to FIGS. 120 to 123, this Example 2 will be described. FIG.120 is an exploded perspective view typically showing a configurationexample of an image forming apparatus according to 22th Configuration.FIGS. 121 a to 121 c are a typical drawing showing forming examples oflead wires of a face plate. FIG. 122 is a block diagram showing theconfiguration of a high-voltage electron source section for supplying ahigh voltage. FIGS. 123 a to 123 c are illustrations of the internalstructure of a casing. In FIG. 120 and FIGS. 121 a to 121 c, symbolssimilar to those shown in FIG. 116 are attached to individualconstituents.

This example is the provision of multiple high-voltage terminals. Asshown in FIG. 120, two air-tight lead-in terminals 7103 are soconstructed to pass through the through holes 7104 at two corners of therear plate 7011. The configuration of a face plate 7011 in this caseassumes a pattern of lead wires being led from two corners as shown inFIG. 121 a. Besides, the lead wire pattern of two corners is not limitedto this, but, for example, a configuration of disposing the lead wiresat three or four corners is allowable as shown in FIGS. 121 b and 121 c.Incidentally, with respect to those similar in the configuration of FIG.120 to the above examples, their description, configurations,manufacturing methods and the like will be omitted.

To supply a high voltage to the above air-tight lead-in terminal 7103and form an image, a high-voltage electron source is required and willbe described referring to FIGS. 122 and 123.

In FIG. 122, reference numeral 701 denotes a high-voltage electronsource, 702, a control circuit, 703, a driving circuit, 704, atransformer and 705, a voltage feedback for stabilizing the outputvoltage. FIG. 123 is a view for explaining the casing configuration andFIG. 123 a is an external view of a display panel with the members shownin FIGS. 121 and 122 incorporated inside the apparatus, FIG. 123 b is asectional view showing the configuration of the casing interior of thedisplay panel viewed from the direction of the arrowhead A and FIG. 123c is a structural drawing of the display panel after the removal of theback plate of the casing viewed from the direction of the arrowhead B.Reference numeral 802 denotes a vacuum panel of a display deviceaccording to FIG. 122, 803, a driving board for driving the vacuum panel802, 804, the FPC for electrically connecting the vacuum panel 802 andthe driving board 803, and 805, high-voltage wires for connecting thehigh-voltage electron source 701 and the air-tight lead-in terminal7103.

From an unillustrated DC electron source in an image forming device, avoltage is inputted to the transformer 704 in the high-voltage electronsource 701. The input DC is boosted to a desired voltage value in thetransformer 704 and the high voltage is outputted from the transformer704. To suppress a voltage fluctuation at the voltage output, thevoltage is fed back (705) and controlled in the control circuit 702 andthe controlled voltage is sent to the transformer 704 via the drivingcircuit 703. The voltage used in this example is set to a voltage outputof 10 mA at 10 kV. In preparing a high-voltage power supply 701 foroutputting this voltage value, the diameter of a core becomes on theorder of 50 mm if the transformer 704 of the electron source 701 iscomposed of a single transformer, whereas the diameter of a core can bereduced if this power supply employs a transformer 704 composed ofmultiple transformers. If the transformer 704 is composed of twotransformers, for example, the outline diameter of a core can be reducedto the order of 30 mm because a value of current to be undertaken by onetransformer becomes a half. Similarly, if it is composed of fourtransformers, a value of current to be undertaken by one transformerbecomes a quarter and its diameter amounts to the order of 25 mm. Inbrief, downsizing the diameter of a core enables a thinnerimplementation of a transformer 704 and accordingly a high-voltage powersupply 701. In the sectional structure of an image forming apparatus 801shown in FIG. 123 b, for example, a thinner high-voltage power supply701 makes it possible to thin down the depth of the whole image formingapparatus 801. Since air-tight lead-in terminals 7103 are located atcorners of the casing 801, count must be taken of the guide of wires indetermining the place of disposing a high-voltage power source 701.Here, as shown in FIGS. 123 b and 123 c, a high-voltage power source 701was located near the air-tight lead-in terminal 7103 at a corner of thecasing 801.

As described above, location of high-voltage terminals at multiplecorners of a vacuum panel and further composition of multiplehigh-voltage power supplies could contribute to a thinner implementationof the whole apparatus. Besides, the disposition of multiple air-tightlead-in terminals reduced the gradient of luminance. This can be said toa configuration advantageous for the implementation of a larger area.

Example 3

Using FIGS. 124 a and 124 b, Example 3 according to 22th Configurationwill be described. FIG. 124 a is a plan view of a vacuum panel viewedfrom the side of a face plate and FIG. 124 b is a sectional structuralview near the high-voltage terminal structure part viewed from the A-A′direction of FIG. 124 a. Incidentally, like symbols are attached toindividual parts similar to those of the above respective examples,while the description thereof and their configurations and manufacturingmethods are omitted.

In this example, a high-voltage output part is so arranged as to beformed at the side of a face plate. As shown in FIGS. 124 a and 124 b, a1 mm diameter through hole is formed at the position of the wiring widthcenter of lead wires 7100 on the face plate 900 to assure the electricconduction to the lead wires 7100 and at the same time an Ag paste ofconductive member 901 is applied to the inner periphery of the throughhole, then the vacuum air-tightness is assured by embedding the outputpart with a frit glass serving as the sealing material 902. According tothis configuration, the creepage distance of insulation to an electrodebody such as printed wires formed at the side of the rear plate 7001 canbe assured, so that this is advantageous to a discharge prevention.

(23th Configuration)

With respect to the configuration of leads in use for the high-voltagepower supply, there is a problem that a high resistance in theconnection part with a high-voltage lead wire would induce a secondarydischarge due to the degassing by heating in case of occurrence of adischarge. As countermeasures against this problem, lowering theresistance in the contact part suppresses heat generation, thus enablingthe secondary discharge to be eliminated. By increasing the connectionlength between a high-voltage lead wire and an interconnectionconductive film or between a metal backing and an interconnectionconductive film or by lowering the sheet resistance of aninterconnection conductive film, the resistance in the connection partcan be reduced. From an estimate of the occurring frequency of asecondary discharge for varied connection length, both the connectionlength W1 [mm] between the interconnection conductive film layer and ahigh-voltage lead wire and the connection length W2 [mm] between theinterconnection conductive film layer and a metal backing layersatisfying a relation for the sheet resistance r [Ω/□] of theinterconnection conductive film:W1,W2>(2.5×r)^(1/2)  (1)

(1) enables a secondary discharge to be suppressed. Hereinafter,examples of 23th Configuration will be shown.

Example 1

FIGS. 125 a to 125 g show the fabricating process of a lead wire in usefor the high-voltage power supply.

First, lead wires 4021 are prepared by the printing process (FIG. 125a). Wires were prepared using silver paste so that the sheet resistanceis equal to or lower than 0.1Ω/□. Next, an interconnection conductivefilm 4025 was prepared similarly by the printing process (FIG. 125 b)For the conductive film, a mixture of carbon to the glass paste is usedto prepare it at a thickness of 2 μm. At that time, the sheet resistanceof an interconnection conductive film 4025 was 50Ω/□. The connectionlength W of a relay conductive film was set at W=150 mm in such a manneras to fully satisfy the relation (1). Next, an insulating black stripe4022 was prepared similarly by the printing method (FIG. 125 c). Thethickness of the insulating black stripe 4022 was set to 3 μm. Thirdly,fluorescent material layers RGB 4008 were prepared similarly by theprinting process (FIG. 125 d). The fluorescent materials used are of P22type, a fluorescent material of an average grain size of 5 μm was usedfor each of R, G and B to make a 15 μm fluorescent material layer 4008.Fourthly, an aqueous solution containing colloidal silica, surfactantand the like was applied onto the fluorescent material layer surface,first to wet the convexo-concave part of a fluorescent material layer,then to spray the solution of a polymethacrylate-based resin with aplasticizer dissolved in a non-polar solvent such as toluene and xyleneonto the fluorescent material surface. After spreading o/w type dropletsput on the convexo-concave fluorescent material surface by using a spincoater, the moisture and the solvent constituent are dried and removedto prepare a 3 μm filming film 4028 (FIG. 125 e). Next, with a mask 4029in use for the aluminum evaporation having an opening only in the imagearea covering over the filming film 4028, a 1000 Å thick aluminum wasdeposited thereon (FIG. 125 f). Finally, this substrate was heated to450° C. at a temperature-rising rate of 1° C./min in a baking furnaceand cooled at a temperature-falling rate of −2.5° C./min aftermaintaining the above high temperature for 30 min, thereby removing theresin intermediate layer by the pyrolisis (FIG. 125 g). After a removalof the filming resin 4028, the metal backing layer 4009 is in contactwith the fluorescent material layer 4008, the black stripe layer 4022and the interconnection conductive layer 4025 as covering them.

Example 2

FIG. 126A is a plan view of an electrode part and FIG. 126 b is asectional view taken on line F-F′ of FIG. 126A. In FIGS. 126A and 126 b,like symbols are attached to constituents similar to those shown inFIGS. 125 a to G.

The interconnection conductive layer 4025 comprises 3 μm thickblack-silver type wires and its sheet resistance is 0.5Ω/□. Theconnection length W2 between the interconnection conductive film 4025and the metal backing 4009 is adopted to be 5 mm long so as to fullysatisfy the equation (1). The high-voltage lead wire 4021 is a 2 mmdiameter tungsten wire and penetrates an electron source substrate 4004to butt against the interconnection conductive film 4021, so that thecontact is ensured. Since the diameter of the connection part is 1.8 mm,the connection length W1 between the high-voltage lead wire 4021 and theinterconnection conductive film 4025 amounts to the correspondingcircumference, i.e. 5.7 mm, which fully satisfies the equation (1). Thedistance L from the image area and the spacer 4020 to theinterconnection conductive film 4025 was set to 12 mm.

A method for preparing on the interconnection conductive film 4025,insulating black stripes 4022, a fluorescent material layer 4008 and ametal backing layer 4009 are similar to that of Example 1 of 23thConfiguration.

Example 3

Next, another example will be described. In this example, a relayconductive film 4025 was prepared using white-silver wires. Besides, inthis example, an insulating black stripes 4022 was extended to theinterconnection conductive film 4025 as the underlying film thereof.Thereby, even when using white-silver wires, only the margin of a blackband was visible and no feeling of hindering an image was provoked. Asthe interconnection conductive film material, not only those used in theabove examples, but a conductive film containing ruthenium oxide can bealso used.

Example 4

In this example, an image forming apparatus was manufactured in whichthe face plate formed as with Example 1 according to 23th Configurationwere opposed to the electron source on which are placed electronemission devices formed in an array on a substrate. FIG. 176 a is a planview of an electrode part of this example and FIG. 176 b is a sectionalview taken on line F-F′ of FIG. 176 a. In FIGS. 176 a and 176 b, likesymbols are attached to constituents similar to those shown in FIGS. 125a to G. In this example, the interconnection conductive film 4025 formedon a transparent substrate 4023 was made into the shape of a band andmade equal in length nearly to one side of the metal backing 4009.Symbols W1 and W2 denote the connection length between the lead wire4021 and the interconnection conductive film 4025 and the connectionlength between the metal backing 4009 and the interconnection conductivefilm 4025, respectively. As seen from FIG. 176 a, in this example, theconnection length W2 between the metal backing 4009 and theinterconnection conductive film 4025 was chosen to be a little longer.As a result, even if a discharge occurs, no secondary discharge wasobserved near the interconnection conductive film.

(24th Configuration)

In a relation of the face plate to the rear plate, especially to theelectron source substrate, the following a configuration can be used.

First, the following tasks have been present regarding these relations.In a conventional image forming apparatus, use is made of a lightgeneration phenomenon due to the collision of electrons emitted from anelectron source with fluorescent materials of an image forming member,but the following issues have been involved in this.

Issue 1: Electric field concentration associated with the layout of anelectrode in the cathode vicinity area;

Issue 2: Charging of an insulating member in the anode vicinity area(Charging due to reflected electrons); and

Issue 3: Charging of an insulating member in the cathode vicinity area(Charging due to positively charged particles).

The above disturbing actions caused a local charging in the vicinal areaso as to distort the beam orbital or induce a break down discharge,thereby leading to a decline in the dielectric withstanding voltage ofelectron emission devices. The above issues will be specificallydescribed below.

Issue 1:

The electron beam emission apparatus can be macroscopically regarded asa parallel planar capacitor comprising a pair of cathode and anode.Except for the peripheral region of a gap between the cathode and theanode, a parallel electric field is formed in a great majority part. Theelectric field strength is basically uniform, but a parallel electricfield is broken in the peripheral region of a cathode and an anode andan electric field concentration point takes place at the metal-insulatorboundary, that is, at the potential base-substrate.

Based on the computation result of electric fields, the electric fieldstrength at the potential base-substrate boundary is found to be approx.1.3 times that of the internal space in the cathode-anode gap for theconfiguration in which the area of cathode is the same as that of anode.The electric field emission is generally not symmetric and electrons arelikely to emit from the cathode side. The electric field concentrationassociated with the geometric layout mentioned above is understood aselectric field emission of electrons from the cathode-substrateboundary. If the above electric field emission is induced, this electricfield concentration in this boundary region, forming one of theoccurring causes of a deviation of the beam orbital and a localdischarge associated with the substrate charging of an electron beamemission apparatus, entailed a problem that moderation by thenon-selection period of an electron source is impossible, because ofappearing under application of an accelerating voltage to the anoderegardless of whether emission or non-emission of electron beam emissiondevices on the cathode.

Issue 2:

Referring to FIG. 127, Issue will be described. In FIG. 127, the imageforming apparatus is so constructed that a metal backing 610 is formedas the anode and an image forming member 606 comprising fluorescentmaterials and black stripes is formed in the image forming area. In suchan image forming apparatus comprising planar-type electron emissiondevices, as shown in FIG. 127, about 5 to 20% are scattered backward(backscattered electron beams e⁻) out of the electron beams irradiatedonto the image forming member 606 comprising fluorescent materials forgenerating visible rays by the collision of electron beams and blackstripes and the aluminum-made metal backing 610 serving for a lightreflection layer and intrude again into the metal backing 610 to which ahigh voltage is applied by the electric field. Furthermore, part of thisbackscattered electron beam strikes the face plate 605 and the side wall609 made of an insulator such as glass to produce the gas emission byadsorbed gas release and the secondary electron emission. In conformitywith the emission efficiency of secondary electrons in the insulator,positive electric charges (δ−1) times the quantity of incident electroncurrent are generated in the insulator glass. On account of a lowconductivity, electric charges generated in the insulator areaccumulated to cause a local charging of the face plate, thus disturbingthe electric field. By this disturbance of the electric field, a desiredelectron beam orbital becomes unobtainable, so that color mismatching orthe like occurs in some cases. Besides, when adsorbed gases arereleased, a break down discharge becomes likely to occur by the electronavalanche, thus leading to damages to the electrode or wires (603 and604) at the side of the rear plate 601 and further to electron emissiondevices 602.

Issue 3:

By a reaction at the collision of electrons with an image forming memberand ionization of atmospheric gases inside the apparatus, positive ionsare generated. These positive ions are accelerated in a directionopposed to the flow of electrons emitted from the electron source by theelectric field created between the electron source and the image formingmember by the accelerating electrode and reach onto the electron source.On the other hand, in the electron source, plenty of insulating portionsnecessary for the patterning of device electrodes of electron emissiondevices are present. For this reason, when the positive ions havingarrived at the electron source charges insulating portions of theelectron source, electrons emitted from electron emission devices arecurved toward the charged insulator portions, the orbital deviates, thusentailing problems such as shift in light emitting position. Besides, aprobability of a discharge or the like arising from charged charges israised, thereby damaging the reliability and life of the apparatus.

The disturbance of an electric field or discharges springing fromproblems as mentioned above was a great issue related to the highfineness/high color purity and further the reliability for a planar-typeimage forming apparatus.

As a method for implementing an image forming apparatus usingsurface-conduction electron emission devices in a simpler configuration,the present inventors invent a system constituting a simple-matrix typeelectron source composed of many surface-conduction electron emissiondevices arranged in an array by respectively connecting a pair ofopposed device electrodes with row direction wires and column directionwires, which can give an appropriate driving signal in row direction andin column direction to select many surface-conduction electron emissiondevices and to control the emission quantity of electrons. Also in sucha simple-matrix type image forming apparatus using surface-conductionelectron emission devices, there is a fear that charging occurssimilarly on the surface of an insulator member and the electron orbitalis affected. The above problem of a shift in the electron orbital takesplace also in an electron beam emission device using no fluorescentmaterial as electron irradiated member as with the image formingapparatus.

Then, it is the object of this configuration to provide a highwithstanding voltage electron beam emission device and image formingapparatus in which the charging of the cathode side insulating part, theelectric field emission of the marginal part and charging of the anodeinsulating part are prevented, the emitted electron orbital isstabilized and a discharge is suppressed by specifying the electricpotential within a minimum extent.

By employing the configuration mentioned below, the electric fieldemission of the cathode-second substrate boundary in the utmostperiphery is suppressed, no local charging is also present and furthereven when driving electron emission devices in utmost periphery edge,the electron beam scattered backward by image forming members such asfluorescent materials never enter outside the image forming section suchas face plate and side wall of insulators. Furthermore, the charging ofthe cathode associated with the release of positive charged particlesfrom the fluorescent material under an accelerating electrode issuppressed. Thereby, the charging disturbing the electric field anddischarges damaging electrodes or electron emission devices aredrastically reduced and the high fineness/high color purity and furtherthe reliability/safety of a planar-type image forming apparatus areimproved.

One example of 24th Configuration will be described referring to FIG.128. FIG. 128 is a perspective view of an image forming apparatus towhich the electron beam emission device of this configuration is appliedand shows a partly cut away panel to disclose the internal structure.FIG. 129 typically shows a section of the image forming apparatus inFIG. 128 viewed from the Y direction.

In FIG. 129, an electron source 11001 with surface-conduction electronemission devices 11015 arranged in the shape of a matrix is fixed to therear plate 11002. Opposite the electron source 11001, a face plate 11003with fluorescent material film 11007 and metal backing 11008 as anaccelerating electrode inside the glass substrate 11006, as an imageforming member, is disposed via a support frame 11004 made of aninsulating material, while a high voltage is applied between theelectron source 11001 and the metal backing 11008 from an unillustratedpower supply. These rear plate 11002, support frame 11004 and face plate11003 are sealed to each other with frit glass or the like and anenclosure comprises the rear plate 11002, the support frame 11004 andthe face plate 11003.

Besides, on the surface of the cathode side substrate, or electronsource 11001, a potential specifying film made of a SiO₂ film is formedwithin a given extent (extent designated with a broken line in FIG. 128)of the district excepting individual electron emission devices 11015 andthe wires eclectically connecting them and this extent is a potentialspecifying part 11009. On letting d, A, B and C be the distance betweenthe metal backing 11008 and the electron source 11001, the maximumregion actually irradiated by electrons emitted from individual electronemission devices 11015 on the metal backing 11008 as the anode-sidepotential specifying part, the anode-side potential specifying part,i.e. laid-on region of the metal backing and the cathode-side potentialspecifying part as shown in FIG. 129, perpendicular lines are droppedfrom the utmost extremities of the region B towards the electron source11001 and on a region C, d greater in either direction than the regionenclosed by these perpendicular lines in parallel to the surface of theelectron source 11001, the cathode-side potential specifying part 11009is situated. Namely, the X-direction and Y-direction length of theregion E shown in FIG. 129 is equal to d (regions A, B, C, E and F areindividually indicated by X-direction line segments in FIG. 128, but areconsidered similarly also in Y direction). Furthermore, the anode-sidepotential specifying part 1108 is situated on a region 2αd greater ineither direction parallel to the surface potential-specified as theanode than the utmost extremities of the maximum region A actuallyirradiated by electrons emitted from individual electron emissiondevices 11015. Namely, the X-direction and Y-direction length of theregion F shown in FIG. 129 is equal to 2αd. In this example, thedistance d between the electron source 11001 and the metal backing 11008was set to 5 mm and α was set to 0.6 mm.

Next, the operation of this example will be described.

On applying a voltage to individual electron emission devices 11015through the out-of-vessel terminals Dox1 to Doxm and Doy1 to Doyn,electrons are emitted from electron emission devices 11015.Simultaneously to this, a high voltage of 5 kV is applied to the metalbacking 11008 (or unillustrated transparent electrode) through thehigh-voltage terminal Hv to accelerate electrons emitted from electronemission devices 11015, thus forcing them to strike the inner surface ofthe face plate 11003. Thereby, fluorescent materials of the fluorescentmaterial film 11007 are excited and emit light, so that an image isdisplayed.

As shown in FIG. 130 a, for example, the fluorescent material film 11007may be so arranged as to have fluorescent materials 11007 a in a stripepattern comprising red (R), green (G) and blue (B) placed in sequenceand black conductive materials 11007 b placed between them. Besides, asshown in FIG. 130 b, fluorescent materials 11007 a corresponding toindividual colors of red (R), green (G) and blue (B) may be so arrangedas to be placed in individual openings of the black conductive member11007 b with circular openings provided in zigzag shape.

Meanwhile, in a planar-type image forming apparatus with an acceleratedelectrode provided at the anode including this example, raising theaccelerating voltage is required to assure the light emission luminance.Thus, the voltage applied between the anodic metal backing 11008 and thecathodic potential specifying part 11009 amounts to the order of 20 kVin a greater case and the electric field in the region where a parallelelectric field at the anode-cathode gap is formed amounts even to 1kV/cm to several tens of kV/cm. In such an outermost shell anode-cathoderegion, however, the spatial symmetry is broken as in the gap betweenboth electrodes and accordingly the electric field becomes a status ofdeviating from parallelism and being curved. In particular, at theboundary between the anode-cathode and the insulating member, theelectric field concentration takes place and locally about 1.3 times theinner gap. Besides, it is almost electron emission from the cathode sidewhen the electron emission associated with the electric fieldconcentration becomes usually at issue. Thus, if the voltage applicationpart of the anode viewed from the cathode final end side is not justabove, the anode is so arranged as to be smaller than the cathode, theelectric field concentration of the cathode-side extremity is lightened.Furthermore, if the anode final end is so arranged as to recede by atleast the anode-cathode distance d to the inner side, i.e. the electricfield application region side in the projection surface to the cathodefrom the cathode extremity, the anode final end cathode distance issubstantially suppressed by 1/√2 and the electric field concentration atthe cathode side can be lightened to a negligible level. Needless tosay, even securing a larger difference of projection boundary of theanode-cathode extremity than d is allowable if the electric fieldconcentration at the cathode side is lightened.

Next, a more preferred anode-cathode arrangement of this example will bedescribed referring to FIG. 131. FIG. 131 is an enlarged sectional viewof the main part of a face plate.

In FIG. 131, numeral 12005 denotes a face plate comprising soda limeglass with an ITO film 12011, a transparent conductive film provided forimproving the conductivity, a fluorescent material 12006 provided insidethe panel which is covered with a metal backing 12010 of an aluminumfilm. The situation that primary electrons emitted from electronemission devices 12002 of the outermost periphery are scattered backwardat an angle of θ from the incident direction and backscattered electronsare re-accelerated by a parallel electric field, is typicallyrepresented. Symbol d denotes a space between the face plate 12005 andthe rear plate 12001, which is substantially equal to the anode-cathodedistance. Symbol F denotes a distance from the periphery of thefluorescent material 12006 to which primary electron beams areirradiated to the end of the conductor metal backing 12010 and the ITOfilm 12011.

Setting the origin to an incident point of a primary electron emissionbeam on the aluminum metal backing 12010 as shown in FIG. 131 andconsidering the x-axis and the y-axis as illustrated, the orbital of theelectron beam backscattered at a backscattering angle of θ is asfollows: x = v₀t  sin   θ,  and$y = {{\frac{e\quad E_{y}}{2m}t^{2}} - {v_{0}t\quad\cos\quad{\theta.}}}$

Here, v0 is an absolute value of velocity of the backscattered electronbeam just after the backscattering and e and m are respectively thecharge and the mass of an electron. Ey and t are the field intensity inthe y-direction and the time. Incidentally, a parallel electric field isassumed here and the field intensity in the x-direction, Ex is set to 0.

Next, the distance x (θ)=F of the electron beam accelerated again by theelectric field to the arrival (y=0) will be evaluated. For this purpose,the following relations are used and substituted into the aboveequations, then after the transformation, one obtains$V_{0} = \sqrt{\frac{2\quad\alpha\quad e\quad V_{a}}{m}}$$E_{y} = \frac{V_{a}}{d}$ F(θ) = 2  α  d  sin   2  θ.

Here, α an Va are the energy ratio of the primary electron beam to thebackscattered electron beam and the accelerating voltage of the primaryelectron beam applied to the face plate, respectively. α greatly dependsupon the material quality, shape, configuration and the like of theincident member of the primary electron beam and generally, α=0.6 to 1.F takes a maximum expressed in the following expression at θ=π/4: F=2αd.Namely, the backscattered electron beam generated at the peripheral partis found to land again at a maximum distance of 2αd from the peripheralpart.

By disposing a conductor more than 2αd apart from the peripheral part ofthe image forming section and further by disposing the side wall partoutside it based on the above consideration, the crash of thebackscattered electron beam to the insulating part or the side wall partsuch as glass outside the image display area is eliminated. And,charging or break down discharge associated with the emission ofsecondary electrons or gases is reduced and highly fining/highly colorpurifying of a planar-type image forming apparatus and the reliabilityas device advances.

Next, a further preferred anode-cathode arrangement of this example willbe described referring to FIG. 131 as an enlarged detail of a rear plateconfiguration. By the crash of electrons emitted from the electronemission part 12002 onto the inner surface of the face plate 12005, thefluorescent material 12006 emits light, but phenomena of particlesdeposited on the fluorescent material film 12006 or the metal backing12010 to be ionized/scattered takes place in addition to thislight-emitting phenomenon. Among these scattered particles, positiveions are accelerated toward the side of the electron source 12003 by avoltage applied to the metal backing 12010 and flies in a parabolicorbital corresponding to an initial velocity perpendicular to theelectric field.

Here, let Va be a potential difference between the electron source 12003and the metal backing 12010, eVi [eV] a maximum value ofhorizontal-direction initial kinetic energy of positive ions, m [kg] themass of a positive ion, +q [C] the quantity of a charge, V_(in) thevertical initial velocity, and V_(it) the horizontal initial velocity,the time t needed till a positive ion generated on the surface of themetal backing 12010 arrives at the electron source 12003, a distance ofd apart and the horizontal move distance ΔS in the direction parallel tothe surface of the electron source 12001 are expressed in terms of:$\begin{matrix}{{{{V_{i\quad n}t} + {\frac{qVa}{2{md}}t^{2}}} = d},} & (1) \\{{{Vi} = \frac{V_{i\quad n}^{2} + V_{it}^{2}}{2m}}{and}} & (2) \\{{\Delta\quad S} = {V_{it}{t.}}} & (3)\end{matrix}$

At this time, the maximum arrival extent as conditions of a positive ionis given by the following conditions (4) and (5): $\begin{matrix}{q = {{+ 1}{e\lbrack C\rbrack}\quad{and}}} & (4) \\{{v_{i\quad n} = {{0\lbrack {m/S} \rbrack}.{Then}}},} & (5) \\{{\Delta\quad S\quad\max} = {2d \times {\sqrt{\frac{V_{it}}{Va}}.}}} & (6)\end{matrix}$

Incidentally, in this example, since the total thickness of the metalbacking 12010 and the fluorescent material 12006 is not greater thanapprox. 50 μm, it is allowable in practical use to employ the distance dbetween the electron source 12001 and the metal backing 12010 as thedistance between the rear plate 12001 and the face plate 12006.

Assuming that a positive ion generated on the surface of the metalbacking 12010 jumps out in a direction parallel to the surface of theelectron source 12003 on receipt of all the energy obtained by thevoltage applied to the metal backing 12010, the moving distance ΔS tillthis positive ion arrives at the electron source 12003 becomesΔSmax=2d  (7),

on substituting Va for Vi in the equation (6).

Namely, from the actual colliding position of electrons on the metalbacking 12010 to the surface of the electron source 12003, aperpendicular is drawn and the extent of a radius 2d around the foot ofthe perpendicular on the inner surface of the electron source 12003 is adistrict at which positive ions generated on the surface of the metalbacking 12010 can arrive.

Thus, if the extent satisfying at least Eq. (7) is potential-specified,there is no field indefinite surface in the flight direction of positiveions generated on the surface of the metal backing 12010 and thecharging of the electron source 12001 is eliminated. In this example,since the potential specifying part at the cathode side is disposed atleast d apart horizontally and outward from the potential specifyingpart at the anode side and further the potential specifying part at theanode side is disposed at least 1.2 d apart similarly horizontally andoutward from the electron beam irradiated region as mentioned above, thepotential specifying part at the cathode side is disposed to 2.2 d apartoutward from the irradiated region and as a result, this potentialspecifying part satisfies the Eq. (7). Needless to say, even if the sizeof the potential specifying part is enlarged than the above extent, itfollows that the extent satisfying Eq. (7) is potential-specified andtherefore the enlargement is allowable.

Besides, a resistance value of the potential-specifying filmconstituting the potential-specifying part is relatively high, but thearea ratio of the potential-specifying film to the wholepotential-specifying part is within 30% and satisfactory for specifyingthe potential because the other part is covered with a conductivematerial of a sufficiently low resistivity such as an electrode made ofa metal. Namely, the potential-specifying part need not to all comprisea conductive material of a low resistivity and may comprises acombination of high and low resistivity. In this case, it preferablycomprises a conductive material not greater than 1×10⁵Ω/□ in surfaceresistivity for not less than 50% of the whole area and a conductivematerial not greater than 1×10¹²Ω/□ in surface resistivity for the rest.

Since the provision of a potential-specifying part on the cathode-sidesubstrate eliminates the occurrence of charging the inner surface of theface plate 12005 as described above, the orbital of an electron emittedfrom the electron emission part 12002 was stabilized and a good imagefree from positional discrepancy was obtained. Besides, a probability ofcaused discharges becomes extremely low and a highly reliable imageforming apparatus was obtained.

Ordinarily, the applied voltage between a pair of device electrodes12016 and 12017 of an electron emission device is on the order of 12 to16V, the distance d between the metal backing 12010 and the electronsource 12001 is on the order of 2 mm to 8 mm and the applied voltage Vato the metal backing 12008 is on the order of 1 kV to 10 kV. In thisexample, the applied voltage between a pair of device electrodes 12016and 12017 of an electron emission device, the distance between the metalbacking 12010 and the electron source 12001 and the applied voltage Vato the metal backing 12008 were set to 14 V, 5 mm as mentioned above and5 kV, respectively.

Incidentally, the potential-specifying part in this configuration issmaller in resistance than the substrate in a minute region comprisingthe arrangement pitch of device electrodes, e.g. in the x-direction andthe y-direction and the ratio of the specified region of potential canbe recognized as not smaller than 30%.

(25th Configuration)

With respect to a relation between the face plate and the rear plate, aconfiguration with the latter greater than the former can be taken. Forexample, a rear plate of 900 mm×580 mm size and a face plate of 850mm×530 mm size can be used.

A plurality of surface-conduction electron emission devices are on arear plate jointly serving for a substrate and wired in the shape of amatrix to form an electron source, then an image forming apparatus wasmanufactured using this. In FIG. 132, Numeral 13101 denotes a rear platemade of soda lime glass making up electron emission devices, 13105, anelectron emission section, 13109, a face plate comprising soda limeglass with a metal backing and a fluorescent material formed, 13111, anouter frame, 13403, X-direction wires, 13406, Y-direction wires, 13316,a driving printed circuit board for driving the image display device and13206, an FPC for connecting the X- and Y-direction wires 13403 and13406 and a printed board 13316, respectively. Incidentally, leading ofwires can be done, for example, from three directions for a 10 inchsquare image display section or from four directions for a 30 inchsquare image display section. Next, examples of this configuration willbe described.

Example 1

In FIG. 132, an image forming apparatus with the FPC and the printedboard connected is shown in a separated arrangement of the FPC, but aunified arrangement is allowable.

First, the ACF is stuck to a connection position of the FPC 13206 to theX-direction electrode wires 13403, as external lead wires of the rearplate 13101. Next, the X-direction electrode wires 13403 of the rearplate 13101 and the FPC 13206 needed for connecting to the printed boardtherefrom are set to the joining position and the X-direction electrodewires 13403 is registered to make them into concordance. When the FPCelectrode 13207 of the FPC 13206 coincides with the X-directionelectrode wires 13403 of the rear plate 13101, the FPC 13206 and theimage forming apparatus are moved under a thermo-press sticking tool.Thereafter, the therm-press sticking tool was brought down tothermo-press stick the FPC 13206 and the X-direction electrode wires13403 to each other by using the ACF and the joining of the FPC 13206and the X-direction electrode wires 13403 was completed. In this manner,the joining of the FPC 13206 and the X-direction electrode wires 13403was completed to join one side thereof. A similar joining wasaccomplished regarding four necessary sides of the X-direction electrodewires 13403 and the Y-direction electrode wires 13406. Afterward, aconnector (unillustrated) attached to the FPC 13206 joined to the rearplate 13101 is inserted in the connector part of the printed substrate13316 and the connection of the rear plate 13101 and the printedsubstrate 13316 was completed. On giving any 14V voltage signal to theX-direction wire and 7V voltage signal to the Y-direction wire to applya 5 kV anode voltage to the metal backing of the face plate, any goodquality image free from discharges was obtained.

In the image forming apparatus manufactured thus, since its externallead electrode is present only on the rear plate, a prober or the likecould be dropped from above only down to the rear plate to perform anelectrification treatment, thereby enabling a voltage or current toeasily flow through the electrodes. According to this approach, a poorcontact of the electrode part is almost eliminated and consequently auniform image can be produced.

Besides, since the joining of the FPC is performable without turningover an image forming apparatus, there is no trouble of holding nor fearof cracking involved in turning over the image forming apparatus and thetime taken for the joining can be shortened. Besides, as compared withthe joining without inversion, the joining device is simple and easy tohandle and accordingly the joining can be accomplished almost free ofdefective products.

Example 2

Example 2 according to 25th Configuration will be described below.

The dimension used in this example was 900 mm×580 mm for a face plateand 850 mm×530 mm for a rear plate. This face plate, an outer frame andthis rear plate are used to prepare a panel, but a method for preparinga panel is partly similar to that of Example 1 according to thisconfiguration and therefore only different parts will be described here.

FIG. 133 is a front view of one example of image forming apparatus. InFIG. 133, like symbols are attached to constituents similar to those ofFIG. 132. In FIG. 133, Numerals 13201 and 13105 denote a rear platecomprising soda lime glass making up electron emission devices and anelectron emission section.

First, on a substrate, the above electron emission section 13105 isformed in advance. Besides, to the inside surface of the face plate ofthe image forming apparatus, a fluorescent material is applied inadvance and further a conductive metal backing is formed on thefluorescent material surface.

To these face plate, outer frame and rear plate 13201 and an exhaustpipe (unillustrated) and so on, low-melting point glass is applied.After the alignment of the face plate and the rear plate, they are fixedwith a jig or the like, put into an electric furnace, heated to abovethe melting point of the low melting point glass and joined to completea hermetic vessel. Thereafter, an electrification treatment is carriedout through wires by using a prober and finally the exhaust pipe issealed.

Next, a method for connecting the external lead wire of the imageforming apparatus manufactured thus and the FPC will be described.

In FIG. 133, the status of connecting the FPC and the printed board tothe image forming apparatus is shown. First, with the face plate keptdownward, the hermetic vessel is set on a press sticking device. Next,the ACF is stuck to the position of connecting the FPC 13206 to theX-direction electrode wires 13403, as external lead wires of the rearplate 13201. Then, the X-direction electrode wires 13403 of the rearplate 13201 and the FPC 13206 needed for connecting to the printed boardtherefrom are set to the joining position and the X-direction electrodewires 13403 is registered to make them into concordance. When the FPCelectrode 13207 of the FPC 13206 coincides with the X-directionelectrode wires 13403 of the rear plate 13201, the FPC 13206 and theimage forming apparatus are moved under a thermo-press sticking tool.Thereafter, the therm-press sticking tool was brought down tothermo-press stick the FPC 13206 and the X-direction electrode wires13403 to each other by using the ACF and the joining of the FPC 13206and the X-direction electrode wires 13403 was completed. In this manner,the joining of the FPC 13206 and the X-direction electrode wires 13403was completed to join one side thereof. A similar joining wasaccomplished regarding four necessary sides of the X-direction electrodewires 13403 and the Y-direction electron wires 13406 of the rear plat13201. Afterward, a connector (unillustrated) attached to the FPC 13206joined to the rear plate 13201 is inserted in the connector part of theprinted substrate 13316 and the connection of the rear plate 13201 andthe printed substrate 13316 was completed. On giving any 14V voltagesignal to the X-direction wire and 7V voltage signal to the Y-directionwire to apply a 5 kV anode voltage to the metal backing of the faceplate, any good quality image free from discharges was obtained.

With the image forming apparatus manufactured thus, different fromExample 1 according to 25th Configuration, an electrification treatmentand a FPC joining is carried out with the face plate set downward, butonly the difference between the rear plate and the face plate comingdownward at the setting causes no difference especially in the process.Since its external lead electrode is present only on the face plate likethis, a prober or the like can be dropped from above only down to theface plate to perform an electrification treatment, thereby enabling avoltage or current to easily flow through the electrodes. According tothis approach, a poor contact of the electrode part is almost eliminatedand consequently a uniform image can be produced.

Besides, since the joining of the FPC is performable without turningover an image forming apparatus, there is no trouble of holding nor fearof cracking involved in turning over the image forming apparatus and thetime taken for the joining can be shortened. Besides, as compared withthe joining without inversion, the joining device is simple and easy tohandle and accordingly the joining can be accomplished almost free ofdefective products.

Example 3

Third example adapting the 25th configuration of the present inventionwill be described below.

The face plate size and the rear plate size of the present embodimentwere 300 mm×250 mm and 350 mm×300 mm, respectively. In the same manneras that in the foregoing first example of the 25th configuration of thepresent invention, an electron emitting part 13105 and electrodes werepreviously formed in the rear plate 13101. Also, fluorescent materialswere previously applied to the inner side surface of the face plate13109 of an image display apparatus and a metal backing havingconductivity was formed on the surface of the fluorescent materials. Lowmelting point glass was applied to the thus prepared face plate 13109,an outer frame 13111, the rear plate 13101, and an exhaust pipe (notshown in the figure) and the face plate 13109 was aligned with the rearplate 13101. The rear plate and the face plate were aligned so thattheir end face of one sides or two sides were matched to each other andfixed by jigs. The FIG. 134 a illustrates that end face of the rearplate and the face plate were matched to each other in one sides and theFIG. 134 b illustrates that end face of the rear plate and the faceplate were matched to each other in two sides. After being fixed by jigsor the like, the resulting body was heated in an electrical furnace tothe melting point of the low melting point glass or higher to join thoseplates and other members and complete an air-tight container.

Next, a panel was manufactured using the face plate, the outer frame,and the rear plate. Since the method for manufacturing the panel wasalmost the same as the above described manufacturing method for thefirst embodiment of the 25th configuration, description only fordifferent points of the manufacturing method will be given below.

The FIG. 135 is a front view of an image display apparatus, which is oneexample. In the figure, the same reference numbers are assigned to theconstituent parts same as those of examples described above. After therespective constituent parts were manufactured in the same manner asdescribed before for the first example of the 25th configuration,electrification treatment was carried out through the wiring by a proverand finally the exhaust pipe was sealed. Lead wires led out the thusmanufactured image display apparatus and FPC were connected by thefollowing method.

The FIG. 135 shows the image display apparatus being connected with theFPC and a printed substrate. At first, an ACF was attached to thex-direction electrode lead 13403, which was a led-out wiring of the faceplate 13201, at the position where the FPC 13206 would be connected.Then, the FPC 13206 necessary to connect from the x-direction electrodelead 13403 of the rear plate 13001 to the printed substrate was set atthe joint position and the x-direction electrode lead 13403 was alignedand made matched. Once the FPC electrode 13207 of the FPC 13206 and thex-direction electrode lead 13403 of the face plate 13201 matched, theFPC 13206 and the image display apparatus were moved to the positionunder a thermo-compression bonding tool. After that, thethermo-compression bonding tool was lowered to thermally bond the FPC13206 and the x-direction electrode lead 13403 by the ACF and joining ofthe FPC 13206 and the x-direction electrode lead 13403 was completed.

In such a manner, joining of the FPC 13206 and the x-direction electrodelead 13403 was completed and joining of one side was done. Joining forother necessary three sides of the x-direction electrode lead 13403 andthe y-direction electrode lead 13406 of the face plate 13201 was carriedout. As illustrated in the FIG. 136, FPC joining might be carried outonly for respective one sides (total two sides) of the x-directionelectrode lead 13403 and the y-direction electrode lead 13406. Afterthat, a connector (not shown in the figure) attached to the FPC 13206joined to the face plate 13201 was inserted into a connector part of theprinted substrate 13316 to complete connection of the face plate 13201and the printed substrate 13316.

Any image with excellent quality could be displayed without electricbreakdown on the resulting image display apparatus by applying anyvoltage signal of 14 V to the x-direction electrode and 7 V to they-direction electrode, and an anode voltage of 5 kV to the metal backingof the face plate.

Since the image display apparatus manufactured in the above describedmanner had lead-out electrodes only in the face plate, processing suchas electrification forming, activating could be carried out only bydropping the prover only to the face plate and consequently voltage andcurrent could easily be applied to the electrodes. As a result, contactfailure of electrode parts scarcely occurred and uniform images could beproduced. Further, since the joining sides were limited to two or threesides and thus the contact parts of the electrode parts were lessened,the contact failure was further lessened as compared with that of theforegoing first and second examples of the present configuration.

Moreover, at the time of joining of the FPC which was done withoutrequiring the image displaying apparatus to be turned over, the any riskdue to the turning over could be eliminated and the time taken to carryout the joining could be shortened. As compared with the case of joiningwithout requiring the turning over, the joining apparatus could besimple and easy, so that the joining could be carried out with scarcefailure. Since the joining sides were limited to two or three sides, thejoining time could be shortened as compared with that for the first andsecond examples of the present configuration.

In accordance with the above described configuration, the manufacturingprocess was made easy, the connection reliability in FPC joining wasenhanced, FPC processing was easily carried out owing to the samejoining direction of the FPC, safety was also improved owing to that thesubstrate was not required to be turned over, and manufacturing timecould be shortened. A highly reliable image display apparatus capable ofproviding images with improved uniformity at high efficiency couldstably be supplied by lessening the connection failure at the time ofmanufacturing of the apparatus in such a manner and thus an imagedisplay apparatus was provided at high productivity.

(26th Configuration)

As the configuration related to the assembly of the image displayapparatus illustrated in the foregoing FIG. 2, the followingconfiguration can be used.

Example 1

The FIG. 137 is a perspective view of an image display apparatus towhich the present 26th configuration is applied. In the figure, thereference number 121 denotes an electron source substrate in which amulti-electron beam source is formed, the reference number 122 denotes asubstrate for display provided with fluorescent materials capable ofemitting light rays by electron beam radiation, and the reference number123 denotes a driving IC directly connected to the wiring end part ofthe electron source substrate 121. The FIG. 138 illustrates across-section figure of a part connecting the driving IC to the wiringend part. The reference number 126 denotes the led out electrode part,which is a part of a column or row wiring formed on the electron sourcesubstrate 121, the reference number 123 a denotes driving IC chips, thereference number 124 denotes bumps made of a metal (e.g. gold) andformed as connection terminals of the driving IC chips 123 a, thereference number 125 is a conductive adhesive, and the reference number127 is a sealing material.

The column or row wiring 126 was formed using a conductive paste byprinting. It was advantageous for the wiring to have a thicker thicknessin order to lower the electric resistance. For that, a thick filmprinting method, especially a screen printing method was preferable tobe employed and a conductive paste of silver, gold, copper, nickel orthe like might be employed. In the case highly precise patterning wasrequired, a rough pattern was formed using a photosensitive paste by ascreen printing method and then exposed and developed to obtain anexcellent wiring pattern. Additionally, after a desired pattern wasformed, in order to remove the vehicle components of the paste, theobtained pattern was fired at a temperature (400 to 650° C.)corresponding to the thermal properties of the glass substrate and thepaste employed.

As the technique of forming a thick film wiring, for example, thetechnique described in Japanese Patent Laid-Open No. 8-227656 might beemployed. That is, an undercoating metal layer was formed on a substrateby electroless plating, an insulating layer with a prescribed patternwas formed on the undercoating metal layer, and a metal layer was formedon gaps of the insulating layer, in other words, the exposed parts ofthe undercoating metal layer by electroplating, and after the insulatinglayer was removed and the exposed undercoating metal layer was removedby etching to form a desired conductive pattern.

The configuration just like the FIG. 138 is one embodiment so-called COG(chip-on-glass) and a series of the processes of mounting the driving ICon the column or row wiring as illustrated in the figure was carried outas following.

After the conductive adhesive 125 was transferred to the bumps 124 onthe driving IC chips 123 a and aligned with the led-out electrode part126 wired on the electron source substrate 121, the driving IC chips 123were moved down and mounted on the electron source substrate 121. Afterthat, the conductive adhesive was hardened by heating or ultravioletbeam radiation and a protective coating 127 of a proper resin materialwas formed on the IC chips 123 to complete the mounting.

The layout of a practical led-out electrode part to carry out the abovedescribed embodiment on the electron source substrate 121 is illustratedin the FIG. 139. In the same figure, the reference number 126 a denotesthe lead-out electrode part of the column side wiring and the referencenumber 126 b denotes the lead-out electrode part of the row side wiring.Also, the reference numbers 128, 129 denote electrode parts connectingthe driving IC and other driving circuit parts to be connected with thedriving IC. In the same figure, the electrode part in the inside of therectangular defined by dotted lines is the connection part with thedriving IC and the M part is a matrix part.

A packaged example of the electrode part 128 (or 129) is illustrated inthe FIG. 140. The reference numbers 121, 123 to 128 denote the sameparts as those to which the same reference numbers are assigned in thedriving IC mounted part of the foregoing FIG. 138. The reference number131 denotes an electrode part made of a conductive material of aflexible cable for connecting the driving IC 123 to another drivingcircuit part and the reference number 132 denotes a resin film. Theelectrode 131 of the flexible cable and the electrode part 128 wereconnected with each other by a conductive adhesive in the same manner asthat for the driving IC.

Additionally, the size of the connection faces of the connection partsof led-out electrodes was different between the column side and the rowside. That is, in the row side, since the total driving current of allof devices flowed if the row was selected, electric current of about0.05 A to 0.2 A and about 1 to 10 A instantaneously flowed in the caseof FE type electron mission devices and in the case of surfaceconduction type electron emission devices used, respectively. Inconsideration of the electric current capacity 0.5 A/mm² of a generalconductive adhesive, the surface area of the connection part wasrequired to be about 0.1 mm² to 20 mm².

On the other hand, in the column side, driving current of the subjecteddevice flowed, about effective current of 5 μA to 20 μA and about 0.2 mAto 2 mA flowed in a subjected FE type electron emission device and in asubjected surface conduction type electron emission device,respectively. For the same reason, the surface area of the connectionpart was required to be about 0.00001 mm² to 0.04 mm². However, sincethe minimum mounting surface area was limited attributed to the size ofthe conductive filler of the conductive adhesive, the mounting surfacearea as narrow as 0.00001 mm², was supposedly limited to be practicallyabout 40 μm square, that is 0.00016 mm².

The capacity component of the wiring crossing part of the multi beamelectron source was measured by LCR meter to find 154 pF at 0.05 pF fora crossing part in the case n=3072. On the other hand, the inducedcomponent in a led-out electrode part of about 30 mm was found 30 nH andthe induced component in a matrix part was found 320 nH by measurement.Consequently, the resonance frequency was computed to be 22 MHz.Further, the rise time of Vs and Ve were investigated and found to beabout 60 nsec and 80 nsec, respectively, and the maximum frequencycomponent was found to be about 17 MHz. As a result, the resonancefrequency could be made higher than the maximum frequency of the drivingsignals and occurrence of ringing waveform could sufficiently besuppressed. In the case a conventional mounting method in which aled-out electrode part and a driving IC part were connected with a flatcable, the induction component in an electric circuit pattern from theled-out electrode part, the 80 mm flat cable part, to the driving IC wasabout 170 nH and the resonance frequency was 18 MHz and owing to thesimilar frequency to the resonance frequency, possibility of occurrenceof ringing waveform was increased.

As described above, the induction component in a connection part of aled-out part and a driving IC could be suppressed to the minimum bydirectly mounting the driving IC to a column or row wiring terminal partand consequently the resonance frequency could be set sufficiently highowing to the capacity components formed in the matrix wiring and imageswith high quality could be displayed while avoiding ringing waveformaddition to driving signals.

Example 2

In this example, since the driving IC mounting in the row wiring endpart was same as that of the first example of the foregoingconfiguration, its description was omitted. The mounting of the drivingIC in the column wiring end part of this example will be described inaccordance with the FIG. 139 and the FIGS. 141 a and 141 b. This examplehad the different configuration of the column wiring end part of A partillustrated in the FIG. 139 from that of the foregoing first example.The FIG. 141 is a magnified illustration of that part. The FIG. 141 a isa magnified illustration of the A part in the foregoing first example.Reference numeral 136 denotes a lead-out electrode part formed by thickfilm wiring and reference numeral 137 denotes the connection part to thedriving IC. The FIG. 141 b is a magnified illustration of the A part inthe present embodiment. Reference numeral 136 a denotes a lead-outelectrode part formed by thick film wiring and reference numeral 136 bdenotes an auxiliary electrode part formed by a thin film wiring.Reference numeral 138 denotes the connection part to the driving ICformed on the auxiliary electrode part 136 b.

Next, the role of the auxiliary electrode part 136 b will be described.Generally, a thick film wiring method is possible to easily form a lowresistant wiring by screen printing or plating but difficult to providesufficient surface flatness and sometimes requires a polishing processor a sufficiently wide surface area for the connection part. On theother hand, a thin film wiring method is possible to form a sufficientlysmooth electrode part in a fine region in the case of employing aphotolithography or an off-set printing method. Practically, the methodcan be selected from the following methods; a method involvingpatterning by a lithographic method and then etching after filmformation in vacuum system of such as a vacuum vapor deposition method,a sputtering method, a plasma CVD method, or the like and a methodinvolving an off-set printing of a MO paste containing organometalsusing a glass concave plate. As a material for the electrode part 136 b,any material having conductivity may be used and examples available forthe material are a metal or an alloy of such as Ni, Cr, Au, Mo, W, Pt,Ti, Al, Cu, Pd, and the likes; printing conductors containing glasstogether with a metal or a metal oxide such as Pd, Ag, Au, RuO₂, Pd—Ag,and the likes; a semiconductor material such as polysilicon; and atransparent conductor such as In₂O₃—SnO₂. Consequently, driving ICmounting can be carried out in the necessary minimum surface area of theconnection part. In this example, a soda lime glass was employed as amulti electron beam source substrate and a Ni thin film formed by anoff-set printing method was employed for the electrode part 136 b. Thethickness, the width, and the length of the electrode part 136 b wascontrolled to be 0.1 μm, 100 μm, and 400 μm.

Further, as described before, the induction component L possiblyrelating to occurrence of ringing signal waveform can de defined asLc+(Lc/n). That is equivalent to the electron emitting operation statefor a large number of electron emitting devices produced if selectiverow driving is carried out. On the other hand, in case of displaying aspecified image and in case a few of devices of selected rows are inelectron emission state, the number represented as the referencecharacter n of the equation L is substantially small and the componentLc can not be neglected. In that case, it sometimes occurs that thereference character L which is estimated to be 30 nH before is estimatedto be at maximum 60 nH, two times as high as the foregoing estimation.To deal with that, as the R component in a series resonance circuit ofLCR, a wiring resistance is actively supplied to the auxiliary electrode14 as to effectively keep the damping coefficient ζ=2R/√(L/C) be 1 orhigher, so that occurrence of ringing can be suppressed, that is,so-called damping effect can be provided.

If an abnormal potential is applied to the wiring by some cause orother, the potential is applied also to the driving IC in the column andit is possible for the driving IC to be broken. To deal with such aproblem, resistance is actively supplied to the auxiliary electrode 136b in the same manner as described above, so that the auxiliary electrode136 b can work as a protection resistance. For example, in the case 3 Vabnormal potential is applied to the wiring side, no potentialapplication to the driving IC is caused by adjusting the possibleflow-in current to the driving IC to be 10 mA and the resistance of theauxiliary electrode to be 300Ω. The auxiliary electrode part 136 bformed by the foregoing off-set printing method was provided with about300Ω as a resistance value from the thick film wiring end part to thedriving IC mounting part 138.

As described above, in the present example, an auxiliary electrode wasformed in a lead-out electrode part by thin film forming method, so thatimage display with higher density could more stably be carried out.

(27th Configuration)

The following configuration can also be a configuration related to theapparatus assembly.

Example 1

The FIG. 142 illustrates the substrate layout of an electric circuitsubstrate constituting a driving electric circuit part of an imagedisplay apparatus to which this 27th Configuration was applied. FIG. 142shows a schematic rear side of the electric circuit substrate in anopposite side view of an image display screen.

The image display apparatus of this example was formed of an imagedisplay part 14103 comprising a face plate 14101 and a rear plate 14102,a driving electric circuit part 14104 for image display, a supportingstructure member 14105 for supporting them, and further an outer member(a cover not illustrated) and an electric power unit 14110. Referencenumeral 14000 denotes a flexible cable.

The driving electric circuit part 14104 could roughly be divided into ascanning circuit substrate (14106 a, 14106 b), a modulation circuitsubstrate (14107 a, 14107 b) an image data generating circuit substrate14108, and an input interface (I/F) substrate 14109. The scanningcircuit substrate generated pulsed scanning signals successivelyselecting the scanning wiring of the image display part 14103 of therear plate 14102 substrate. Since the scanning circuit substratesimultaneously drove right and left scanning wiring of the rear plate14102, it was formed of the scanning circuit substrate 14106 a and thescanning circuit substrate 14106 b. The modulating circuit substrategenerated pulsed modulation signals for carrying out pulse widthmodulation driving of a multi-electron source through a modulation sidewiring rectangularly crossing the scanning wiring of the rear plate14102. In this example, since the size of the image display apparatuswas large, the modulation circuit substrate was divided into twomodulation circuit substrates 14107 a, 14107 b.

The image data generating circuit substrate 14108 converted image datainto modulated data to the modulation circuit substrates (14107 a, 14107b). The input interface (I/F) substrate 14109 has a decoder part whichgave output of R, G, R component signals from input image signals A andseparate synchronous signals (SYNC) superposed on input image signalsand generate various types of timing signals.

In this example, among the electric circuit substrates constituting thedriving electric circuit part 14104, the modulation circuit substrates(14107 a, 14107 b) emitting a large quantity of heat were laid out in anupper part and the image data generating circuit substrate 14108 foroutputting signals to the modulation circuit substrates were laid out inthe lower part. The pair of the scanning circuit substrates (14106 a,14106 b) were laid out in the right and left ends of the image displayapparatus.

The FIG. 143 illustrates the functional block figure of the drivingelectric circuit of the image display apparatus of this example and theFIG. 144 illustrates a timing chart of the apparatus. Reference numeralP2000 denotes an image display part (hereafter called as display panelfor short) comprising a rear plate on which a multi-electron sourceformed of surface conduction type electron emitting devices in a simplematrix structure is arranged and a face plate. In this example, surfaceconduction type devices P2001 in number of 480×2556 were arranged andconnected with row wiring of vertical 480 rows and column wiring ofhorizontal 2556 columns of a matrix, and emitted electron beam from eachsurface conduction type device P2001 was accelerated by high voltageapplied from a high voltage power source P30 and radiated to thefluorescent materials, which were not illustrated, in the face plateside to emit light rays. The not-illustrated fluorescent materials mightbe arranged in various color arrangements corresponding to the usepurposes and in this case color arrangement in RGB vertical stripes wasemployed.

In this example, an application example for displaying television imagesequivalent to those of HDTV on a display panel having the number ofpixels of horizontal 852 (RGB trio)×vertical 480 lines will be describedbelow and it is no need to say the application of a display panel withapproximately the same configuration is possible not only to a HDTV butalso to image signals with different resolution and frame rate, suchhighly precise images of such as NTSC, output images of a computer, andthe likes.

In this example, electrons were emitted from respective devices for aduration corresponding to the pulse width by carrying out pulse widthmodulation and driving the devices on row P2002 selected by scanningcircuits (14106 a, 14106 b). Two-dimensional images were formed bysuccessively scanning lines selected by the scanning circuits.

Description will be given in accordance with the image signal flowbelow. Image signals were sent to the input I/F substrate 14109. Theinput I/F substrate 14109 was formed of P1, P2 blocks. The P1 block wasthe HDTV-RGB decoder part to receive the composite video inputs of HDTVand to output the RGB component signals (shown as T101 of the FIG. 144).In this unit, the synchronous signals (SYNC, shown as T102 of the FIG.144) superposed on the input video signals were separated and samplingCLK signals (CLK1) were generated and outputted. The P2 block was thetiming generation part to generate the following timing signalsnecessary to convert the analog RGB signals decoded in the P1 block intodigital gradation signals for luminance modulation of the display panel:

(a) clamp pulses for d.c. regeneration of the RGB analog signals fromthe P1 block in the analog processing part P3,

(b) blanking pulses for addition of blank periods to the RGB analogsignals from the P1 block in the analog processing part P3,

(c) sample pulses (not shown in the figure) for conversion of RGB analogsignals to digital signals in the A/D part P6,

(d) timing signals for writing in and reading out the line memories P10and the luminance line memories P22, and

(e) scanning control signals Yscan.

The RGB component signals were sent to the image data generatingsubstrate 14108. The image data generating substrate 14108 was formed ofP3 to P10 blocks. The P3 block was an analog processing part for eachoutputted primary color signal from the P1 block and carried out thefollowing operation:

(a) receiving the clamp pulses from the P2 block and carrying out d.c.regeneration,

(b) receiving blanking pulses from the P2 block and adding blankingperiods, and

(c) carrying out amplitude control of primary color signals sent fromthe P1 block and black level control of the primary color signals sentfrom the P1 block.

LPF P5 was a pre-filter means installed in the prior stage to the A/Dpart P6. The A/D part P6 was an A/D converter means to quantize theanalog primary color signals passed through LPF P5 in necessary numberof gradations. The reverse γ table P7 was a gradation characteristicconversion means installed to convert the input video signals to meetlight emitting characteristics of the display panel. In the case theluminance gradation is expressed by pulse width modulation just likethis example, an image display apparatus often has a linear propertythat the quantity of light emission is proportional to the degree of theluminance data. On the other hand, since the video signals are subjectedto a TV picture tube employing a CRT, they are processed by γ-processingin order to correct the non-linear light emission characteristics of theCRT. For that, in the case TV images are to be displayed in a panelhaving linear light emission characteristics just like this example, theeffect of the γ-processing has to be canceled by the gradation propertyconversion means like P7. P10 was horizontal line memory means for eachprimary color signal and gave outputs of luminance data of RGB to themodulation circuit substrate 107 (T105 of the FIG. 144).

The scanning circuit substrates 14106 a, 14106 b were formed of Y-shiftresistor parts P1002, pre-drivers P1003, and switch transistors. EachY-shift resistor part P1002 received horizontally periodic shift clocksand vertically periodic trigger signals to give row scanning startingtriggers and output selective signals for successively scanning the rowwiring P2002 to each pre-driver part P1003 installed for each rowwiring. Each output part for driving each row wiring was constituted,for example, of FET means P1004, P1006. Each pre-driver part P1003 wasfor driving each output part with excellent responding property. The FETmeans P1004 were switch means which selectively applied −Vss=−7 Vpotential to each row wiring electrically communicated at the time ofrow selection. The FET means P1006 was a switching means to carry outelectric communication at the time of no row selection and applied GNDpotential to the row wiring at the time of non-selection. Referencenumeral T112 of the FIG. 144 shows one example of row wiring-drivingwaveforms.

Next, the following is the description of the flow of signals after RGBluminance data, which is line memory outputs P10 from the image datagenerating circuit 14108, is input to the modulation circuit substrate14107. RGB luminance signals in number of 2556 corresponding to thenumber of devices (R1 to R852, G1 to G852, and B1 to B852) in horizontaldirection were outputted during one horizontal period. When thosesignals were transmitted to 2556 drivers connected to the modulationside wiring during one horizontal period, the respective drivers had togenerate pulse width modulation output. In order to carry out datatransmission to the modulation side drivers at high speed, the linememories P10 were, therefore, once transmitted to the luminance linememories P22 each formed of 16 blocks and each line memory P22 was soconfigured as to simultaneously transmit modulation driver data innumber of 160. In other words, the output of each RGB line memory of P10was re-arranged in order corresponding to the fluorescent materialcolors of the panel connected through P2003 and converted to be seriessignals and transmitted to each line memory P22 for luminance signals.

The shift resistor latch circuit P1101 read lines of luminance data(image data) in column wiring number of 2556 from line memories P22 inevery horizontal period by shift clocks (T107 of the FIG. 144), latchedthe data in parallel in latch circuits P11101 b of the shift resistorlatch circuit P1101 by LD pulses like T108 of the FIG. 144, andtransmitted the data of one horizontal column of 2556 signals as a wholeto the PWM generator parts P1102.

The PWM generator parts P1102 installed for each column wiring receivedluminance data (image data) from the latch circuits of the shiftresistor latch circuit P1101 and generated pulsed signals having pulsewidth proportional to the degree of the data for every horizontal periodjust like the waveform shown as T110 of the FIG. 144.

P1104 was switching means comprising transistors and applied +Vs=7 Vvoltage output to column wiring during the period in which the outputsof the PWM generator parts P1102 were valid and earthed the columnwiring during the period in which the outputs of the PWM generator partsP1102 were invalid. One example of the column wiring driving waveformsis shown as reference numeral T111 of the FIG. 144.

Images were formed on the display panel P2000 by successively scanningrow wiring and driving the column wiring with signals of the values ofpulse width modulation of the image data corresponding to the row wiringscanning in a manner described above. In the modulation circuitsubstrate 14107, the driver stages for generating pulse width modulationdriving signals from the luminance line memories were made to be IC(integrated circuits). Each driver IC comprised modulation drivers for160 ch and a shift resistor circuit for transmitting and latching thepulse width modulation data of each driver, a latch circuit, and PWMgenerator. In this example, since shift resistors for shifting luminancedata signals of 160 in number to horizontal 2556 columns of columnwiring, the number of shifts was 320×8=2560 and the PWM generator partand others were formed of 2560 components each. Respectively two rightand left lines of the output ends of 2560 of switching means P1104 werenot connected with the column wiring.

As described below, the quantity of heat generation in each board wasestimated. To calculate the estimation, the number of devices waspresupposed to be of horizontal 852 (RGB trio)×vertical 480 lines andimage signals of 60 Hz progressive scanning were presupposed as inputsignals. Regarding the device characteristics, the device currentflowing in one device at the time of driving at 14V was presupposed tobe 1 mA.

(1) Modulation Circuit Substrate

The heat generation in the modulation circuit substrate is attributed toA: the power loss in the output transistors and B: the power consumptionin the logic parts.

Regarding A: the power loss in the output transistors, in the case theON resistance of one transistor was presupposed to be 100Ω and fullwhite image display was carried out, the power loss would be asfollowing: $\begin{matrix}{{{Plos}\quad A} = {{Ron} \times ({If})^{2} \times 2556}} \\{= {100 \times ( {1\quad{mA}} )^{2} \times 2556}} \\{= {0.3\quad{W.}}}\end{matrix}$

Regarding B: Logic,

as described above, 8-bit luminance data had to be transmitted to 2556PWM generators P1102 during a 1H period (about 30 μs in 480 scanninglines and 60 Hz progressive scanning) and the logic consumption powerfor data transmission became the maximum, that is, the logic consumptionpower to be consumed in the driver IC became the maximum.

That is, the shift operation for transmitting 8-bit data signals innumber of 160 and PWM counter circuit operation were carried out foreach driver IC. Generally, the power consumption of one logic isPlogic=(½)×f×C×(Vlogic)²

wherein the reference character f denotes the operational frequency; thereference character C denotes the logic gate capacity; and the referencecharacter Vlogic denotes the logic operational voltage. In this example,when operation was carried out with shift counter, PWM counter clock=9MHz, 1 W electric power was consumed for every driver IC. The power lossof the driver IC as a whole wasPlosB=1W×16=16 W.

(2) Scanning Circuit Substrate

The heat generation in the modulation circuit substrate is attributed to

A: the power loss in the output transistors and B: the power consumptionin the logic parts.

Regarding B, the operation frequency of the logic of the scanningcircuit substrate was low enough to be neglected.

Regarding A: the power loss in the output transistors (in the case theON resistance of one transistor was presupposed to be 0.2Ω, and per onesubstrate), the power loss would be as following: $\begin{matrix}{{{Plos}\quad A}\quad = \quad{{Ron} \times ( {{line}\quad{{If}/2}} )^{2}}} \\{= {0.2 \times ( {2556\quad{{mA}/2}} )^{2}}} \\{= {0.3\quad{W.}}}\end{matrix}$

(3) Image Data Generation Circuit

The heat generation in the modulation circuit is attributed to mainly B:the power consumption in the logic parts. The power consumption of thelogic parts was about 10 W in the case of operation at 3.3 V of logicoperation voltage.

According to the results of the above described (1) to (3), themodulation circuit substrate 14107 which emitted the highest quantity ofheat was arranged in the upper end of the image display part and theimage data conversion circuit substrate was arranged under themodulation circuit substrate. On the other hand, the pair of thescanning circuit substrates were installed in the right and left ends ofthe image display part. Consequently, the image display apparatus wasenabled to efficiently release heat emitted from the driving electriccircuit part and to be stably operated.

In this example, the heat emitted from the electric circuit substratesconstituting the driving electric circuit part could sufficiently bereleased by spontaneous convection of air taken through air intakeinlets formed in the upper and lower parts of the outer frame.

Subsequently, fan-free configuration was made possible and an extremelycalm image display apparatus was materialized. Especially, in the casethe resolution degree of an image display apparatus was heightened, theheat emission of the logic parts of the modulation circuit substrate washighest and thus such layout of this example would be highly effective.For example, in the case of progressive scanning of 1920 (×3 devicenumbers) of horizontal pixels and 1080 of scanning lines at 60 Hz, theforegoing PWM counter and the shift clock had to be operated at >20 MHz.In that case, even if the operation voltage of the logic could belowered, the size of the logic IC determined by the output voltage ofthe IC could not be changed, so that the logic gate capacity could notbe changed and 2 W electric power was consumed per every driver IC andthe quantity of the heat emitted out of the modulation circuit substratewas increased.

(28th Configuration)

The following configuration can also be a configuration related to theapparatus assembly of the present invention.

The FIG. 145 is a schematic view illustrating the arrangement of theconnector in the rear plate side of a display panel to which the 28thConfiguration is applied. Reference numeral 15001 denotes avacuum-sealed display panel. The detailed structure and themanufacturing method of the display panel will be described later.Reference numeral 15002 denotes flexible cables and connectors to becolumn wiring terminals. Reference numeral 15003 denotes flexible cablesand connectors to be row wiring terminals. Reference numeral 15004denotes an accelerating voltage terminals.

The FIG. 146 is a layout figure of the above described display panel inwhich a control part, a driving part, an electric power part, and othersare mounted. Reference numeral 15005 denotes a modulation driving part.Reference numeral 15006 denotes a scanning driving part. Referencenumeral 15007 denotes an accelerating voltage generation part. Referencenumeral 15008 denotes a control part for the whole apparatus body.Reference numeral 15009 denotes the wiring for accelerating voltage.Reference numeral 15010 denotes an electric power source for theapparatus.

The FIG. 150 is a perspective view illustrating the installationstructure of the above described accelerating voltage terminal andpositioning relations with the row wiring, the column wiring, and theaccelerating electrode. Reference numeral 15101 denotes a rear platewhich is the rear side structure member of the display panel 15001.Reference numeral 15111 denotes a face plate which is the front sidestructure member of the display panel 15001. Reference numeral 15104denotes a supporting frame which is supporting structure member forsupporting the face plate 15111 and the rear plate 15101. Referencenumeral 15131 denotes a cable for supplying accelerating voltage.Reference numeral 15116 denotes an accelerating voltage terminal.Reference numeral 15132 denotes a rubber cap. Reference numeral 15122denotes a through hole formed in the rear plate. Reference numeral 15121denotes a hollow member for supporting the accelerating voltage terminalregion. Reference numeral 15120 denotes a lead wire of the acceleratingvoltage. Reference numeral 15112 denotes an accelerating electrodeformed on the face plate 15111 and electrically connected to theaccelerating voltage terminal 15116 through the lead wire 15120.Reference numeral 15102 denotes an electron source region in which therow wiring, the column wiring, and the electron sources are arranged andwhich is formed on the rear plate 15101.

The FIG. 149 is a block figure illustrating the outline structure of theprocessing part to display images. The reference number 15031 denotes animage input part. The reference number 15032 denotes an A/D convertingpart. The reference number 15033 denotes a timing control part. Thereference number 15034 denotes a signal processing part. The referencecharacter S1 denotes an inputted composite video signal. The referencecharacter S2 denotes a synchronously separated video signal. Thereference character S3 denotes a synchronizing signal separated from thecomposite video signal S1. The reference character S4 denotes an videosignal made to be digital. The reference character S5 denotes amodulation signal. The reference character S6 denotes a timing signal tothe modulation driving part. The reference character S7 denotes ascanning signal. The reference character S8 denotes a timing signal tothe scanning driving part. The reference character S8 denotes anaccelerating voltage.

The video signal input part 31 receives an input of the composite videosignal S1 and separates it into the video signal S2 and thesynchronizing signal S3. The A/D converting part 15032 makes the videosignal S2 digital and outputs the resultant digital video signal S4. Thetiming control part 15033 outputs a driving timing signal for the wholeapparatus based on the synchronizing signal S3. The image signalprocessing part 15034 processes the digital image signal S4 and outputsthe scanning signal S7 and the modulation signal S5. The scanningdriving part 15006 drives the row wiring of the display panel 15001 at avoltage as low as ±10 V or lower through the row wiring terminals 15003following the scanning timing signal S8 and the scanning signal S7. Themodulation driving part drives the column wiring of the display panel15001 at a voltage as low as ±10 V or lower through the column wiringterminals 15002 following the modulation timing signal S6 and themodulation signal S5. The accelerating voltage generation part 15007generates high voltage and supplies the accelerating voltage S8 to thedisplay panel 1. An electron source not shown in the figure is arrangedat the crossing point of the row wiring and the column wiring, which arenot shown in the figure, of the display panel 15001 and electron beam isgenerated by simple matrix driving of the row wiring and the columnwiring to emit light from fluorescent materials, which are not shown inthe figure, of the display panel 15001 and display an image. Thestructure of the display panel 15001 and the electron source will bedescribed in detail later.

The method exemplified for the high voltage generation method for theaccelerating voltage generation means 15007 is a fly-back method or aforward converter method, or the like.

The row wiring terminals 15003 are connected to both sides of rowwiring, which is not shown in the figure, of the display panel 1 anddriven by perfectly same signals by two pairs of scanning driving parts15006. Consequently, the electric current flowing in the row wiring isdispersed in both sides and the partial electric voltage decrease in therow wiring can be suppressed.

In the apparatus, the accelerating voltage terminal 15004, the electricpower source 15007, and the wiring 15009 for accelerating voltage werehigh voltage parts at several kV to 20 kV and other parts were lowvoltage parts at 5 to 15V. The distance L between the high voltage partand the low voltage part was desirable to be 1 mm/kV or wider in termsof safety relevant to discharge withstand voltage. The distance L of thelow voltage part and the high voltage part could easily be kept 20 mm orwider by arranging the respective parts in the layout as the FIG. 146,so that the discharge withstand voltage could be improved and the safetycould be heightened.

Further, since the radiation of noise in the high voltage parts owingthe high voltage generation circuit was high, the low voltage parts suchas the control part 15008, driving parts 15005, 15006 of the apparatuswere enabled to be arranged at positions parted from the high voltageparts and consequently, possibility of erroneous driving of the circuitby the radiated noise of the high voltage parts could be suppressed.

The FIG. 151 is a front view of the rear plate of the foregoing displaypanel. In this figure, flexible cable, which is not shown in the figure(shown as 15002, 15003 in the FIG. 145 and the FIG. 146) is thermallycrimped to electrode parts in the ends of the column wiring 15105 andthe row wiring 15106 by ACF. Also in the rear plate, the distance Lbetween the electron source region 15102 of low voltage parts comprisingthe column wiring 15105, the row wiring 15106, the electron source,which is not shown, and the likes and a hollow part 15122 of theaccelerating voltage terminal in the high voltage parts is preferably0.5 mm/kV or wider in order to keep safety relevant to the dischargewithstand voltage and the capability of the display panel 15001 andfurther preferably 1 mm/kV or wider. The distance L between the electronsource region of low voltage parts and the hollow part 15122 of theaccelerating voltage terminal in the high voltage parts could easily bekept 20 mm or wider by arranging the row wiring terminals, the columnwiring terminals, and the accelerating voltage terminal in the layoutshown as the FIG. 145, so that the discharge withstand voltage in theinside of the display panel 15001 could be improved and the safety ofthe apparatus could be heightened and at the same time the performanceof the panel could easily be kept for a long duration.

Further, in the case the enough distance (20 mm or wider distancebetween the high voltage parts and the low voltage parts) was keptbetween the high voltage parts and the low voltage part, theaccelerating voltage terminal 15004 did not necessarily have to bepositioned in the center of the side of the display panel 15001.Moreover, though being not shown in the figure, the column wiringterminals 15012 and the row wiring terminals 15013 might be positionedalso at any parts in the side.

The present invention can be applied with approximately the sameconfiguration even in the case of application to a vertical oblong typedisplay apparatus. The apparatus may be constituted as shown in the FIG.148 as to have the gravity center in a lower side. The layout is thesame as that of the above described example except that the electricpower source parts 15007, 15010 are arranged in a lower part of theapparatus and the layout of the apparatus inside is slightly changed.

Especially, since the weight of the high voltage power sources is heavy,it is preferable for the power sources to be installed lower than thegravity center of the display panel for improving the stability of thedisplay apparatus installation.

Further, it is preferable that the heat radiating parts of respectivepower sources and the likes are kept from the direct contact with therear plate constituting the display panel. That is for avoiding thedisplay panel being affected with unintentional stress of the heat fromthe power sources.

(29th Configuration)

The following configuration can be employed in the case of electriccharge elimination from an image forming apparatus.

Example 1

The FIG. 152 is a block figure illustrating the configuration of animage display apparatus of the first example to which this 29thConfiguration is applied. A method for electrostatic elimination in thecase of actual drive of the image display apparatus will be describedbelow.

The image display part 16001 is same as the foregoing example. As adriving method, a line-sequential scanning method is employed andgradation display is basically carried out in order to give gradation tothe display images by controlling the total quantity of the lightemission of fluorescent materials by controlling the electron emissionduration within one horizontal scanning duration (1H) with the timeduration of the modulation signals.

In the FIG. 152, the signal separating circuit 16012 is a circuit forproducing horizontally synchronizing signals S2, verticallysynchronizing signals S3, digital image signals S4, and the likes fromimage signals S1 such as NTSC. The circuit comprises a video signalintermediate frequency circuit, a video signal detection circuit, asynchronously separating circuit, a low pass filter, an A/D conversioncircuit, a timing control circuit, and the likes. The reference number16014 denotes a scanning signal side driver for driving row-directionwiring of the image display part and outputs a scanning signal based onthe horizontally synchronizing signals 52 separated and produced by thesignal separating circuit 16012. The reference number 16013 denotes amodulation signal side driver for driving the column-direction wiring ofthe image displaying part and outputs a modulation signal based on thehorizontally synchronizing signal S2, the vertically synchronizingsignal S3, and the digital video signal S4 separated and produced in thesignal separation circuit 16012.

The reference number 16016 denotes a circuit for detecting the electricpower source state of the present image display apparatus and outputs asignal S5 corresponding to ON/OFF of the power source SW. Further, thereference number 16017 denotes a timer circuit to output the signal S6based on the OFF signal of SW for electrostatic elimination of thedisplay apparatus to the controller 16011. At the time when the signalS6 from the timer circuit 16017 is in the active state, a signalcorresponding to Va=0 V is to be outputted. Other than that, the imagedisplay apparatus comprises a high voltage power source 16008 and ananode current detection circuit 16007. Those applied to the foregoingconfiguration example may be employed for the high voltage power source16008 and the anode current detection circuit 16007.

The FIG. 157 illustrates the driving timing of the image display part ofthe image display apparatus of this example. The FIG. 157 illustratesone example of driving timing of the voltage to be applied to the leadwires of the row-direction wiring (that is, the wiring in the side wherescanning signals are supplied) and the column-direction wiring (that is,the wiring in the side where modulation signals are supplied). Thetiming chart of this figure illustrates the voltage applied to therow-direction wiring of I, I+1, I+2 lines at the time of successivelyoperating the lines I, I+1, I+2 of the foregoing image display apparatusand the voltage applied to the column-direction wiring J, J+1, J+2 whichare in the modulation signal side. In this case, 1<I<M−2, 1<JN−2 whereinthe reference character M denotes the number of the row wiring wires andthe reference character N denotes the number of the column wiring wires.In reference with the figure, one horizontal scanning duration Kindicates the display of the I line, K+1 the display of I+1 line, andK+2 the display of I+2 line. The row wiring wires, which are in thescanning side at the time of successive line scanning, are successivelyselected in order for every one horizontal scanning duration (hereafterdenoted as 1H) and scanning signals with crest value −½Vf (Vf means thedriving voltage here and approximately Vf=2 Vth) having the pulse widthapproximately equivalent to 1H are successively applied to the selectedwires of row-direction wiring. After the scanning is carried out for alllines of the row-direction wiring, the scanning ifs repeated againsuccessively from the first row wire. In the column-direction wiring,modulation signals having the crest value of ½ Vf corresponding to thevideo signals to be displayed on the selected rows and synchronized withthe scanning signals to be applied to the row-direction wiring areapplied to all wires of the column-direction wiring. The modulationsignals rise up synchronously with the rise up of the driving signalsand rise up after being kept at the crest value of ½ Vf for durationcorresponding to the video signals (hereafter, the duration from therise up of a modulation signal to the time of rise up is called simplyas pulse width of the modulation signal). The pulse width of amodulation signal is made to correspond to each luminance of RGB threecolors into which a video signal to be displayed on a selected row isdecomposed and actually, it does not have a simple proportional relationto the luminance since correction is variously carried out in order todisplay images with high quality. In such a manner, driving voltage Vfis applied to surface conduction type emission devices of a selected rowfor the pulse width of a modulation signal. Since the emission electriccurrent Ie of a surface conduction type emission device has the abovedescribed clear threshold characteristic, an image corresponding to adesired video signal can therefore be displayed on the selected row.Further, by successively carrying out line driving, an image can bedisplayed on all of the surface conduction type emission devices in theimage display apparatus.

Next, the electrostatic elimination function of this example will bedescribed. As a method for electrostatic elimination driving of an imagedisplay apparatus, it is impossible for an image display apparatus toemploy a method involving a step of stopping Va for a certain period ondetection of alteration ratio of Ie during image display. A detectioncircuit 16016 for detecting the alteration of the power source state istherefore installed to detect the SW of the image display apparatus isturned off and to output the signal of the detection to the timercircuit 16015. The timer circuit 16015 recognizes OFF of the SW signaland outputs the instruction signal S6 (Va=0 V) to carry outelectrostatic elimination driving to the controller circuit 16011 for aprescribed period. The controller circuit 16011 sets the Va control ofthe high voltage power source 16008 at 0 V by a high voltage controlsignal based on the timer circuit 16015.

A timing chart corresponding to the above described control isillustrated in the FIG. 153. At first, in the case the SW is turned offat the time of T1 in the image display apparatus, a logic level signalof OFF is outputted from the SW-ON/OFF detection circuit. The timercircuit 16015 detects the alteration, for example, fall of the signalfrom the H level to the L level in this example, of the signal at theOFF time and drives the timer counter. The timer counter outputs a logicsignal corresponding to Va=0 (in this example, from the L to the Hlevel) for the duration denoted as the reference character Ta determinedby the counter circuit set in the timer circuit inside to the controllercircuit 16011. The controller circuit 16011 detects an alteration of thesignal of the timer circuit 16013 and starts electrostatic eliminationdriving.

The electrostatic elimination driving is carried out for the Taduration, the controller circuit 16011 carries out setting of highvoltage control signal Va=0 to the high voltage power source 16008 andon the other hand, only device driving is carried out, so that thescanning side driver 16014 and the modulation signal side driver 16013are driven as they are. At the time of ending the Ta duration by thetimer counter, the output signal of the timer counter is changed fromthe H level to the L level and the controller circuit 16011 releases theelectrostatic elimination driving on detection of the alteration of thesignal and the device driving is also stopped. In the above describedcontrol, the electrostatic elimination driving is carried out withoutdetecting the anode electric current Ie from the anode current detectioncircuit 16007, however electrostatic elimination driving may be carriedout while taking the anode electric current value Ie into consideration.Substantially, at the time of outputting a signal of the Ta duration ofa timer counter, the controller circuit 16011 detects the anode electriccurrent Ie value and may determine whether electrostatic eliminationdriving should be carried out or not for the value. The determinationmethod to be employed involves steps of comparing the Ie value with aprescribed Ie value using the comparator circuit and determiningperformance of electrostatic elimination driving in the case the Ie isthe prescribed Ie value or higher set in the comparator circuit. Then atthe time when the Ie value lowers to the prescribed value within the Taduration, the electrostatic elimination driving is completed at thatmoment. On the other hand, the Ie value is the prescribed value orhigher even after Ta duration, the electrostatic elimination operationis continuously carried out. In this case, the anode current Ie isconverted into an electric signal (an analog signal or a digital signalthrough the A/D converter) and sent to the comparator circuit. Further,the set Ie value set in the comparator circuit is changed correspondingto the Va value to be applied at the time of display driving on theimage display apparatus.

Further, another method involving a step of setting the Ta durationcorresponding to the state duration of the SW may be employed. In thiscase, the timer circuit 16013 counts ON time based on the signal fromthe SW-ON/OFF detection circuit 16016. If the ON time of the imagedisplay apparatus is short, the Ta duration is shortened and if the Ontime is long, the Ta duration is prolonged. Also in this case, controljust like the above described control method using the comparatorcircuit may be carried out by detecting the anode electric current Ie.Consequently, electrostatic elimination driving corresponding to thedriving duration of the image display is made possible.

Moreover, the other method involving sequential processing by CPU orsequencer or the like installed in the inside of the controller may beemployed for electrostatic elimination driving. The flow chart in thecase of sequential processing is illustrated in the FIG. 154. Thedriving will be described below in reference with the figure.

The ON/OFF state of the SW is determined in the step S10. In the casethe SW is in OFF state, whether electrostatic elimination driving isnecessary or not is detected by detecting the value of the anodeelectric current Ie in the step S11 and if the value is an allowablevalue or higher, it proceeds to the step S12. Next, in the caseelectrostatic elimination driving is carried out, the timer setting iscarried out in the step S12. The electrostatic elimination duration isequivalent to the Ta duration. Next, electrostatic elimination drivingis carried out in the step S13. The electrostatic elimination driving iscarried out for a duration set in the step S12 at the electrostaticelimination condition Va=0 V and in device driving ON state. When theelectrostatic elimination driving is determined to be completed in thestep S14, the value of Ie is again detected in the step S15 and whetherthe electrostatic elimination driving is stopped or not is judged. Inthe case it is determined to stop the electrostatic elimination driving,the device operation is turned off in the step S16.

As described above, in this example, the electrostatic eliminationdriving was made controllable by detecting ON/OFF signal of the SW. Bythis example, the electrostatic elimination driving could be carried outcorresponding to the display duration of the image display apparatus andthe electrostatic elimination effect was heightened and the surfacepotential increase, which is one factor of break down discharge invacuum, was prevented and thus the reliability of the display apparatuswas improved. Further, in the case ON/OFF of the SW were repeated in ashort time (for example in the case of switching the image displayapparatus for TV use to a game use), the electrostatic eliminationdriving could be carried out by the method of this example.

Example 2

The second example to which the 29th Configuration is applied will bedescribed below. This example enables the electrostatic eliminationdriving during image display. Since the configuration of the imagedisplay circuits and the control circuits of the image display are allsame as those of the above described second example, description of themis omitted. In the control method of this example, the duration Ta forcarrying out electrostatic elimination driving is set by a timer circuitin the case the value of Ie detected by the anode electric currentdetection circuit 16007 exceeds a set value of Ie. From the starting ofthe signal of the set Ta, high voltage control signals of Va=0 areoutputted once for several frames while being synchronized with thehorizontally synchronizing signals to carry out electrostaticelimination. Its timing chart is illustrated in the FIG. 155. Thedriving will practically be described in reference with the figure.

At first, anode current Ie is constantly taken in the controller circuit16011 from the anode current detection circuit 16007. A comparatorcircuit is employed in the controller circuit 16011 as same as that inthe above described first example of the present configuration and inthe case the detected value of Ie is a set value or higher, the signalfor it is sent to the timer circuit 16015 through the controller circuit16011 from the comparator circuit. On detection of the input signal, thetimer circuit 16015 outputs a timer signal Ta. A Ta outputting method issame as that of the above described first example of the presentconfiguration. When the timer signal Ta is outputted, the controllercircuit 16011 detects the alteration of the signal (alteration from Llevel to H level) and outputs a signal of Va=0 while synchronizing withthe horizontally synchronizing signals. Since image signals areoutputted at 60 Hz frequency in the case the image signals are NTSCsignals, the above mentioned counter setting is so done as to outputsignals Va=0 V to the high voltage power source 16008 once for 2 field(1 frame) by the counter which counts the horizontally synchronizingsignals and by a synchronizing circuit which synchronizes the signals ofTa and the horizontally synchronizing signals in this example.

Consequently, the high voltage power source 16008 is so controlled as tokeep Va=0 V for about 16 msec and the duration of electrostaticelimination driving during which only device driving is carried outexists once for 1 frame. By carrying out such control described above,electrostatic elimination driving for the display apparatus can beperformed even during image display. Additionally, regarding the settingof the electrostatic elimination driving, the setting can be changed bychanging the set value of the counter which counts the horizontallysynchronizing signals. In the case flicker effect or the like of thefrequency of the electrostatic elimination driving set in this exampleaffects the display of images, the cycle of the electrostaticelimination driving can be prolonged by increasing the set value of thecounter. In that case, the set duration of Ta is better to be prolonged.Further, also in this example, it is made possible to releaseelectrostatic elimination driving in the case the value of Ie isdetected and found that the detected value of Ie is a set Ie value orlower within the duration of Ta. Also, in the case the value of Ie isfound to be a set Ie value or higher, electrostatic elimination drivingis continuously continued even if the duration of Ta is up. Moreover, assame as the above described first example of the present configuration,another method involving sequential processing by CPU or sequencer orthe like installed in the inside of the controller may be employed forelectrostatic elimination driving.

The flow chart in the case of sequential processing is illustrated inthe FIG. 156. The drive of the sequential processing will be describedbelow in reference with the figure.

At first, anode current Ie is determined in the step S17 and in the casethe detected value of Ie is the set Ie value or higher, a timer settingTa for electrostatic elimination driving is performed in the step S18.Next, after prescribed horizontally synchronizing signals are countedbased on the count value previously set from the horizontallysynchronizing signals in the step S19, electrostatic elimination drivingat Va=0 only for the device driving is carried out in the step S 20. Theelectrostatic elimination driving control is same as the above describedcontrol. Then, whether the set duration Ta is up or not is determined inthe step S 21. If the set time is up, the anode current Ie is againdetected in the step S22 and if the detected current is the set value orlower, the Va is set to be a prescribed voltage in the step S23 andnormal image display driving is carried out while the horizontallysynchronizing counter being put in disable state. In the case thedetected Ie value is the set value or higher and electrostaticelimination driving is required, the electrostatic elimination drivingis continuously continued until the Ie value is lowered to the set valueor lower.

As described above, this example enabled the electrostatic eliminationdriving to be carried out even during image display and just like theabove described first example of the present configuration, surfacepotential increase, which is one factor for break down discharge invacuum, could be prevented and the reliability of the display apparatuswas improved.

(30th Configuration)

Description regarding the split driving of an image display screen willbe given below in reference with examples.

Example 1

The FIG. 158 is the perspective view of a display panel employed forthis example and a part of the panel is cut out in order to illustratethe inner structure. In the figure, the reference number 1005 denotes arear plate, the reference number 1006 denotes side walls (a supportingframe), the reference number 1007 denotes a face plate, and the rearplate 1005, the side walls 1006, and the face plate 1007 compose theenclosure (an air-tight container) for keeping the inside of the displaypanel vacuum.

A fluorescent material film 1008 and a metal backing 1009 are formed onthe face plate 1007. A substrate 1001 is fixed in the rear plate 1005and on the substrate 1001, cold cathode devices 1002 in number of N×Mare formed. The surface conduction type emission devices in number ofN×M are arranged in simple matrix wiring of row-direction wiring wires1003 in number of M and column-direction wiring wires 1004 in number ofN electrically divided into two sections.

Next, the method for producing a multiple electron beam source employedfor the above described display panel will be described.

As long as the multiple electron source to be employed for the imagedisplay apparatus of this example is an electron source in which surfaceconduction type emission devices are so arranged as to be connectedthrough simple matrix wiring, any material or shape of the surfaceconduction type emission devices and any production method of thedevices can be employed. However, inventors of the present inventionhave found that it is easy to produce the emission devices havingelectron emission parts or their peripheral parts produced from a fineparticle film and that such emission devices are excellent in electronemission properties. For that, it can be said that such emission devicesare most suitable to be employed for the multiple electron beam sourceof the image display apparatus with a wide screen and high luminance. Inthis example, surface conduction type emission devices having electronemission parts or their peripheral parts produced from a fine particlefilm were therefore employed for above described display panel.

One example of production methods of the multiple electron beam sourceof this example will be described below in reference with the FIG. 159.The FIGS. 159 a to 159 e are process figures illustrating a series ofthe procedure of producing the multiple electron beam source. Themagnified figure of a part of an electron source is diagrammaticallyillustrated in the figure.

At first, a large number of pairs of device electrodes 2301, 2302 areformed by forming a conductive thin film of a metal material on a wellwashed substrate 2309 and finely patterning the thin film by aphotolithographic method. Examples of the materials for the substrate2309 include quartz glass, glass with suppressed contents of impuritiessuch as Na, soda lime glass, a glass substrate produced by forming aSiO₂ film on a soda lime glass by a sputtering method or a CVD method,and ceramics such as alumina. Formation methods of the electrodes 2301,2302 may be selected from methods involving a process of forming thefilm by a vacuum system of such as a vacuum vapor deposition method, asputtering method, a plasma CVD method, or the like and then a processof patterning the film by a lithographic method followed by etching andan off-set printing method using a glass concave plate and anorganometal-containing MO paste. Any conductive material can be used maybe used as the material for the device electrodes 2301, 2302 and, forexample, the following are examples; metals or alloys of such as Ni, Cr,Au, Mo, W, Pt, Ti, Al, Cu, Pd, and so on; printed conductors constitutedof glass, and metals or metal oxides of such as Pd, Ag, Au, RuO₂, Pd—Ag;semiconductor materials such as polysilicon; and transparent conductorssuch as In₂O₃—SnO₂. In this example, a soda lime glass was employed forthe substrate 2309 and a Ni thin film was employed for the deviceelectrodes 2301, 2302. The thickness of the device electrodes wascontrolled to be 1000 [Å] and the gap between the electrodes wascontrolled to be 2 [μm] (in the FIG. 159 a).

Next, a conductive paste is patterned by printing to form thecolumn-direction wiring 2304. At that time, the column-direction wiring2304 is so formed as to be connected with the device electrodes 2301.The wiring is advantageous to be thick since the electric resistance canbe lowered. For that, a thick film printing method, especially a screenprinting method, is preferable to be employed and a conductive paste ofsilver, gold, copper, nickel or the like can be used. The FIG. 159 billustrates that a column-direction wiring wire is disconnected in thecenter part of an electron source and electrically divided into twosections. The edges of the column-direction wiring wire at thedisconnected point is formed to be circular by patterning as illustratedin the figure. By forming in such a manner, the potential distributionis prevented from becoming sharp in the edge parts of the disconnectedpart by high voltage applied to the metal backing, so that occurrence ofelectric discharge to the metal backing from the disconnected part ofthe wiring wire can be avoided. Additionally, in the case furtherprecise patterning is required, an excellent wiring wire shape can beformed by forming a rough pattern using a photosensitive paste by ascreen printing and then carrying out exposure and development. Afterthe formation of a desired pattern, firing at a temperature (400 to 650°C.) corresponding to the thermal properties of the used paste and usedglass substrate is carried out in order to remove the vehicle componentsfrom the paste (the FIG. 159 b).

Then, interlayer insulating films 2305 are formed in the crossing partsof the row-direction wiring wires and the column-direction wiring wires.The interlayer insulating films 2305 are produced from a mixture ofcomponents properly selected from, for example, glass substances mainlycontaining lead oxide, PbO, Pb, B₂O₃, ZnO, Al₂O₃, SiO₂, and the likes.The thickness is not specifically restricted as long as insulationproperty is surely retained, and normally it is 10 to 100 μm andpreferably 20 to 50 μm. The interlayer insulating films are formed byapplying a paste produced by mixing frit glass mainly containing leadoxide, a proper polymer such as ethyl cellulose, and a vehicle selectedfrom organic solvents to prescribed positions by a screen printingmethod and then firing the paste. Since it is required for theinterlayer insulating films only to cover the crossing points of thecolumn-direction wiring wires and the row-direction wiring wires, theshapes of the films are not limited to the illustrated ones and mayproperly be selected (FIG. 159 c).

The row-direction wiring 2306 is formed on the interlayer insulatingfilm. Since the wiring is advantageous to have a lowered electricresistance, the thick film printing method capable of thickening thefilm thickness is preferable to be employed. Therefore, as same as thecolumn-direction wiring formation, wiring is carried out by formingwiring wires using a conductive paste by screen printing and then firingthe paste. At that time, the respective wiring wires are so formed as tobe connected with the device electrodes 2302 (FIG. 159 d). Finally, theconductive thin film 2303 of the surface conduction type electronemission devices is formed (FIG. 159 e).

The following is detailed description of a driving method of themultiple electron beam source.

In this case, the description in details will be of a driving method forimage formation by so-called screen split driving method wherein groupsof surface conduction type electron emission devices are divided intoupper and lower sections in the column direction and line scanning iscarried out simultaneously in both sections to form images.

The FIG. 160 is a block figure illustrating the configuration example ofthe driving circuit for driving the display panel. In the figure, theimage data 17000 to be displayed is generated from, for example, TVsignals such as NTSC signals or generated in a personal computer,inputted, and housed in the image memory 17109. To simplify thedescription, the image memory 17109 is set to be VRAM, a common dualport RAM type, and enabled to read the housed content even during thedevelopment of images by CPU which is not shown in the figure. Also tocontrol the driving of the devices in the upper half section of thedisplay panel 17108, a line memory 17105 a, a modulation signalgenerator 17107 a, and a scanning circuit 17102 a are installed and tocontrol the driving of the devices in the lower half section, a linememory 17105 b, a modulation signal generator 17107 b, and a scanningcircuit 17102 b are installed.

The control circuit 17103 generates address signals to take image dataof every one line out of the image memory 17109 for the upper screen andthe lower screen in this order and at the same time outputs read signalsto the image memory 17109 and outputs reciprocally writing signals tothe line memories 17105 a, 17105 b. Since the connection of the imagememory 17109 to the respective line memories 17105 a, 17105 b is made incommon, it is required to carry out writing reciprocally to the linememories 17105 a, 17105 b. The control circuit 17103 outputs memory loadtiming signals Tmry-a and Tmry-b when the respective data of every oneline is housed in the respective line memories 17105 a, 17105 b and thenreads out the data of the next line.

The modulation signal generator 17107 a outputs driving signalscorresponding to the data housed in the line memory 17105 a to thecolumn-direction wiring terminals Dy1 to Dyn and the scanning circuit17102 a outputs driving signals to the row wires on which display is tobe done among the row-direction wiring wires connected to the terminalDx1 to Dx(m/2) based on the Tscan-a signals sent from the controlcircuit 17103. Simultaneously, the modulation signal generator 17107 boutputs driving signals corresponding to the data housed in the linememory 17105 b to the column-direction wiring terminals Dz1 to Dzn andthe scanning circuit 17102 b outputs driving signals to the row wires onwhich display is to be done among the row-direction wiring wiresconnected to the terminal Dx((m/2)+1)) to Dxm based on the Tscan-bsignals sent from the control circuit 17103. That is, images aredisplayed while two lines of the display panel 17108 are simultaneouslybeing driven under control.

In such a manner, the display panel 17108 is driven under control by thescreen split driving method, so that light emission can simultaneouslybe carried out on two lines of the display panel 17108 and the scanningfrequency of the line can be lowered to ½ and thus the emission durationfor every one line can be two-fold to give two-fold luminance.

As described above, by employing the multiple electron beam source anddividing the column-direction wiring wires of this example, imagedisplay with high luminance and high quality could be carried outwithout causing unnecessary electron emission.

Example 2

This example described below is also an application example usingemploying the multiple electron beam source of which thecolumn-direction wiring wires are divided into two sections. Since thisexample differs from the above described first example of the presentconfiguration in the disconnection part of the column-direction wiring,only the points different from those of the first example will bedescribed below.

The following is the description of one example of the multiple electronbeam source production method of the present example in reference withthe FIG. 161. The FIGS. 161 a to 161E are process charts illustrating aseries of procedure of producing the multiple electron beam source. Inthe FIG. 161, a magnified figure of a part of the electron source isdiagrammatically illustrated.

The FIG. 161 a illustrates the electron source at the time when thedevice electrodes 2301, 2302 and the column-direction wiring wires 2304′are formed. The device electrodes 2301, 2302 are formed from the samematerial and have the same structure as described for the foregoingfirst example of the present configuration. The column-direction wiringwires 2304′ are those produced from the same material as described inthe first example. The different point from the first example is that nopatterning is carried out in the disconnection part. The FIG. 161 billustrates the electron source at the time of the interlayer insulatingfilms 2305′ are formed in the crossing points of the column-directionwiring and the row-direction wiring. The different point from the firstexample is that the interlayer insulating films 2305′ are so formed asto cover the disconnection part of the column-direction wiring 2304′. Byforming such a manner, the edges of the disconnection part are preventedfrom being electrically exposed to the high voltage of the face plate.In other words, electric discharge to the face plate from thedisconnection part owing to the electric field concentration upon theedge parts of the disconnection part can be prevented. Further, it isanother advantageous point that the shape patterning can be eliminatedin such a disconnection part of the column-direction wiring of thisexample.

Moreover, since the disconnection part is formed in the wire crossingparts, arrangement on the matrix wiring can be simplified and the wiringdensity to satisfy the demand of heightening image quality can easily beincreased.

The material and the formation method of the interlayer insulating films2305′ are same as those of the first example. The FIG. 161 c illustratesthe row-direction wiring 2306′ formed in the interlayer insulating films2305′. The material and the formation method of the column-directionwiring are also same as those of the first example.

Same methods and processes of the foregoing first example were employedfor the formation method of the conductive thin film of the surfaceconduction type emission devices, electrification forming process,activation process, the driving method of the multiple electron beamsource, and the likes.

As described above, by driving the image display apparatus in the samemanner as the first example using a multiple electron beam source, inwhich column-direction wiring is split, of this invention, image displaywith high luminance and high quality could be carried out withoutcausing unnecessary electron emission.

(31st Configuration)

The following are the configurations as the connection configuration ofthe mounting part and the lead wires.

Example 1

The FIG. 162 a is a perspective view illustrating the wiring connectionstructure of the first example to which the 31th configuration isapplied and the FIG. 162 b is the cross-section figure. The referencenumber 2321 denotes an electron source substrate on which a multipleelectron beam source is formed, the reference number 2322 denotes asubstrate for display provided with fluorescent materials emitting lightrays by electron beam radiation, the reference number 2323 denotes acable connecting the wiring part of the electron source substrate 2321and the driving electric power source, and the reference number 2324denotes the driving power source. The length of the flat cable in therow-direction wiring side and the length of the flat cable in thecolumn-direction wiring side were controlled to be about 100 mm and 50mm, respectively, in this example and the induction components of therespective cables were controlled to be about 100 nH and 50 nH,respectively.

The capacity component of wire crossing parts of the multiple electronbeam source was measured by a LCR meter and found to be 0.04 pF forevery crossing part and 154 pF (=c) in the case of n=3072. The FIG. 163is an equivalent circuit figure of the multiple electron beam source ofthe display panel. In the FIG. 163, the reference number 25002 denotesan electric power source for supplying the pulsed signal Vs to therow-direction wiring wires 25004 and the reference number 25003 denotesan electric power source for supplying the pulsed signal Ve to thecolumn-direction wiring wires 25005. Devices 25009 exist in respectivecrossing points of the row-direction wiring wires 25004 and thecolumn-direction wiring wires 25005 and respectively have capacitor Cmand inductance Lm for respective crossing points. The referencecharacter Lr denotes the induction component of the connection cableparts of the lead parts of the row wires and the electric power source25002 and the reference character Lc denotes the induction component ofthe connection cable parts of the lead parts of the column wires and theelectric power source 25003. In this example, the induction component Lrwas composed of about 30 nH induction component in a lead electrode partof about 30 mm and about 100 nH induction component in the flat cable(about 100 mm) connecting a driving electrode and a lead electrode part.The induction component Lr was thus estimated to be 130 nH. Theinduction component in the matrix part (induction components Lm×n ofwires connecting the devices) was about 280 nH. The induction componentLc of the connection parts of the column wire lead parts and theelectric power source was composed of about 30 nH induction component inan about 30 mm electrode lead part and about 50 nH induction componentin the flat cable (about 50 mm) connecting a driving power source and alead electrode part. Lc/n was thus estimated to be 0.08 nH. Accordingly,L=130+280+0.08=410.08 nH, C=154 pF and the panel characteristicfrequency was calculated to be 22 MHz.

On the other hand, the rise time of Vs and Ve illustrated in the FIG.163 was measured and found to be about 60 nsec and 80 nsec,respectively, and the highest frequency component was found to be about17 MHz. Consequently, the resonance frequency could be heightened morethan the highest frequency of the driving signals, so that occurrence ofringing could sufficiently be suppressed. The foregoing description isof the electron emission driving state of a large number of electronemission devices in the case of line-selection driving.

In the case a specified image was displayed, in other words, in the caseonly a few devices of selected rows were in electron emission state, thenumber denoted as n in the expression L became small, so that Lccomponent could sometimes not be neglected. At the maximum, Lc/ncomponent was 80 nH (the induction component of one column-directionwiring) and the resonance frequency was computed to be 18.3 MHz. In thiscase also, the resonance frequency could be heightened more than thehighest frequency of the driving signals, so that occurrence of ringingcould sufficiently be suppressed.

In this example, flat cables were employed for the connection parts ofthe row- and column wiring terminal parts and the driving electric powersources, however no restriction is imposed and tabs and flexible wiresmay be employed.

Example 2

In this example, an example employing an electron source substrate whosematrix wiring part is divided into two groups will be described. Thesurface conduction type electron emission devices in number of N×M aredivided into two groups and each group is connected in the form of asimple matrix through row-direction wiring wires in number of M/2 androw direction wiring wires in number of n. The FIG. 164 is a perspectiveview of a display panel of this example. The same reference charactersand numbers are assigned to the same constituent parts as those of theforegoing FIG. 158. Since the respective constituent parts are asdescribed in the FIG. 158, description of them is omitted in this case.

The length of the flat cable of the row-direction wiring and the lengthof the flat cable of the column-direction wiring were controlled to beabout 100 mm and 50 mm, respectively, in this example. The inductioncomponents of the respective cables were controlled to be about 100 nHand 50 nH, respectively. In this case, the capacity component of wirecrossing parts of the multiple electron beam source was measured by aLCR meter and found to be 0.04 pF for every crossing part and 154 pF(=c) in the case of n=3072. As illustrated in the FIG. 163, theinduction component Lr of the connection cable parts of the lead partsof the row wiring and the electric power source 25002 was composed ofabout 30 nH induction component in a lead electrode part of about 30 mmand about 100 nH induction component in the flat cable (about 100 mm)connecting a driving electrode and a lead electrode part. The inductioncomponent Lr was thus estimated to be 130 nH. The induction component(induction components Lm×n of the wiring connecting devices) in thematrix part was about 280 nH. The induction component Lc of theconnection cable parts of the lead parts of the column wires and theelectric power source 25003 was composed of about 30 nH inductioncomponent in an about 30 mm electrode lead part and about 50 nHinduction component in the flat cable (about 50 mm) connecting a drivingsource and a lead electrode part. Lc/n was thus estimated to be 0-08 nH.Accordingly, L=130+280+0.08=410.08 nH, C=154 pF and the panelcharacteristic frequency was calculated to be 22 MHz.

On the other hand, the rise time of Vs and Ve illustrated in the FIG.163 was measured and found to be about 60 nsec and 80 nsec,respectively, and the highest frequency component was found to be about17 MHz. Consequently, the resonance frequency could be heightened morethan the highest frequency of the driving signals, so that occurrence ofringing could sufficiently be suppressed. The foregoing description isof the electron emission driving state of a large number of electronemission devices in the case of row-selection driving.

In the case a specified image was displayed, in other words, in the caseonly a few devices of selected rows were in electron emission state, thenumber denoted as n in the expression L became small, so that Lccomponent could sometimes not be neglected. At the maximum, Lc/ncomponent was 80 nH (the induction component of one column-directionwiring) and the resonance frequency was computed to be 18.3 MHz. In thiscase also, the resonance frequency could be heightened more than thehighest frequency of the driving signals, so that occurrence of ringingcould sufficiently be suppressed.

In this example, flat cables were employed for the connection parts ofthe row- and column wiring terminal parts and the driving electric powersources, however no restriction is imposed and tabs and flexible wiresmay be employed.

Accordingly, this configuration is effective even in the case the matrixis split in just like the foregoing manner.

(32nd Configuration)

The following configuration can be employed for arrangement of therespective parts of an image display apparatus.

Example 1

An image display apparatus of this example to which the 32ndconfiguration is applied will be described in reference with the FIG.165. The FIG. 165 is a diagrammatically illustrated cross-section figureof the image display apparatus.

The image display apparatus is constituted by housing a display panel4100 in an outer casing 4115. The display panel 4100 is constituted byinstalling a face plate 4107 on which fluorescent materials are arrangedand a rear plate 4105 on which electron emission devices are arranged onthe opposite to each other. The reference number 4101 denotes an airoutlet for ventilating the warmed air in the panel to the outside byspontaneous convection and 4102 denotes an air inlet. The referencenumber 4103 is a front plate made of a transparent resin and installedas to protect and prevent the face plate 4107 from damages. The frontplate 4103 may additionally be provided with a function of improving thecontrast by inserting an optical filter. The reference number 4104denotes a driving circuit part for electrically driving the displaypanel 4100 and electrically connected to lead wires of the display panelthrough flexible wiring (not shown in the figure).

The temperature control of the face plate 4107 and the rear plate 4105composing the display panel 4100 of this example will be described belowin reference with the FIG. 165 and the FIG. 166.

At first, electron beam emitted out of an electron source of the rearplate 4105 is accelerated by high voltage (anode voltage: Va) applied tothe metal backing on the face plate 4107 and comes into collisionagainst fluorescent materials formed on the face plate 4107. Though apart of fluorescent materials emit light owing to the collision, thecollision of electron beam mostly generates heat. The quantity of theheat generation depends on the types of the images, however, the timeseries average can be supposed to be almost constant and it is set to beQf (W/m²) per unit surface area. On the other hand, the electric currentturns back to the driving circuit 4104 through the matrix wiring in therear plate 4105 and during that time, heat is generated in the wires,device electrodes, and the electron emitting parts on the rear plate. Assame in the face plate, the quantity of the heat generation is supposedto be almost constant in terms of the time series average and set to beQr(W/m²).

In the driving circuit part 4104, electric current is applied to drivethe electron source of the rear plate 4105. To apply the electriccurrent, inner loss is caused in the driving circuit and it becomes heatgeneration source. In respect of that too, the heat generation quantityis supposed to be almost constant in terms of the time series averageand set to be Qd (W/m²). The relations of those values is illustrated inthe diagrammatically illustrated circuit figure in the FIG. 166. In thisexample, Qf=100 (W/m²), Qr=20 (W/m²), and Qd=40 (W/m²) and in this case,by setting d=5 mm, the temperature of the face plate 4107 and of therear plate 4105 was found to be almost same (about 40° C. at the timewhen the ambient temperature was 20° C.). That is, since the face plate4107 and the rear plate 4105 respectively have mutually different heatgeneration quantities, it is clear that these plates respectively havedifferent temperature if the temperature is determined based only onthose relations, however by positioning the driving circuit part 4104,which is another heat generation source at position satisfying d=5 mm,especially the temperature of the rear plate 4105 is supposed to beaffected (more specifically is increased) to make the temperature of theface plate 4107 and the rear plate 4105 same. Consequently, thedifference of the thermal expansion of both plates was lessened and thethermal stress was suppressed and no image torsion and color shift waspractically caused. Since no movable part, such as a fan, exists in suchconfiguration of this example, the image display apparatus is suitablefor a display for household use and a display of a computer which arerequired to be calm.

Example 2

The configuration including the outer casing of this example is the sameas the foregoing first example of the present configuration. Thedifferent point of this example is that the device current (If, Ie) ismade possible to be increased by elongating the device length in orderto maintain the same luminance under the decreased Va in relation to thedesign of the display panel. In the case of this example, Qf=100 (W/m²),Qr=80 (W/m²), and Qd=40 (W/m²) and in this case, by setting d=30 mm, thetemperature of the face plate 4107 and the rear plate 4105 was found tobe almost same (about 40° C. at the time when the ambient temperaturewas 20° C.). Like that, in the case of a display panel employing surfaceconduction type electron emission devices, the ratio of the heatgeneration quantity of the face plate and the heat generation quantityof the rear plate is changed by altering the design value of the panel.Accordingly, just like the case of the foregoing first example, thedifference of the thermal expansion of both plates could be lessened andthe thermal stress could be suppressed and no image torsion and colorshift was practically caused.

Example 3

The configuration of this example is illustrated in the FIG. 167. In theFIG. 167, the different point from that of the foregoing first exampleof the present configuration (refer to the FIG. 165) is that fans 4301,4302 for forcible convection generation are installed in the air ports4101, 4102 formed in the outer casing 4115. The fan 4301 is a fan fortaking air out and so made as to generate axial flow in the upperdirection of the figure. On the other hand, the fan 302 is a fan fortaking air in and so made as to generate axial flow same in the upperdirection of the figure. By these two fans, flow rate of average 0.9 m/sto the cross-section surface area in the outer casing was obtained.

The respective heat generation quantities were Qf=100 (W/m²), Qr=20(W/m²), and Qd=40 (W/m²) and in this case, by setting d=10 mm, thetemperature of the face plate 4107 and the rear plate 4105 was found tobe same (about 30° C. at the time when the ambient temperature was 20°C.). The reason for that was supposedly attributed to that thetemperature of the face plate was considerably lowered by the forcibleconvection and that the arrangement of the driving circuit part 4104 ismade so as to suppress the effect of the generated heat thereof on therear plate 4105.

Accordingly, in this example just like the case of the foregoing firstexample, the difference of the thermal expansion of both plates could belessened and the thermal stress could be suppressed and no image torsionand color shift was practically caused. Since such configuration of thisexample is capable of suppressing the panel temperature increase even inthe environments where the ambient temperature is increased, the displayapparatus with the configuration is suitable to be used in places suchas plants and outdoors where the outer air can not be shut out.

Example 4

The configuration of this example is illustrated in the FIG. 168. In theFIG. 168, the different point from that of the foregoing example 1 ofthe present configuration (refer to the FIG. 167) is that a dust-prooffilter 4401 is installed in the air port in the outer casing 4115.

In this example, the respective heat generation quantities were same asthose of the foregoing example 1 of the present configuration; Qf=100(W/m²), Qr=20 (W/m²), and Qd=40 (W/m²). Owing to the installation of thefilter, the conductance was deteriorated and the average flow rate wasdecreased to about 0.45 m/s, about a half of that of the example 3. Inthis case, by setting d=7.5 mm, the temperature of the face plate 4107and the rear plate 4105 was found to be almost the same (about 35° C. atthe time when the ambient temperature was 20° C.). Accordingly, as sameas the foregoing the first example, the difference of the thermalexpansion of both plates could be lessened and the thermal stress couldbe suppressed and no image torsion and color shift was practicallycaused.

Since such configuration of this example is capable of blocking dust bythe filter even in the environments more or less containing dust, thedisplay apparatus is suitable to be used in places similar to outdoors.

Besides the above described examples, displays of various types ofdesigns were actually produced and thermal simulation based on theactually measured data was carried out to examine the arrangement of thedriving circuit part 4104 as to eliminate the temperature difference ofthe face plate 4107 and the rear plate 4105 and it was found that thetemperature difference was almost eliminated by arrangement at the dvalue within 5 to 30 mm in an image forming apparatus with the screensurface area of 30 to 100 inch.

(33rd Configuration)

One embodiment of driving of an apparatus related to the presentinvention will be described below.

A block figure of a driving circuit of a SED panel is illustrated in theFIG. 169. The reference number H100 denotes a display panel wherein aplurality of electron emission devices are matrix wired by row wiringand column wiring and the electron beam emitted from the electronemission devices is accelerated by high voltage applied from a highvoltage electric power source H103 and radiated to the fluorescentmaterials, which are not shown in the figure, to give light emission.The not-shown fluorescent materials may be arranged in various colorarrangements corresponding to the use purposes and color arrangement inthree-color vertical stripes of red, green, and blue colors (hereafterreferred to RGB) is employed in this case.

In this example, the configuration of displaying video signal inputs isillustrated and the same configuration can deal with not only the videosignals but also various types of image signals, for example, outputsignals of a computer.

The reference number H104 denotes a decoder part for receiving the videosignal inputs modulated in TV manner and separating the synchronizingsignals superposed on the video signal inputs and outputting them. Inthe case of dealing with various types of TV manners, it is proper toinstall decoders exclusive for the object TV manners.

The reference number H105 denotes the scanning conversion part foradjusting the scanning signals corresponding to the number of theeffective scanning lines of the video signal inputs and the number ofthe scanning lines of the display panel H100 and generating effectivescanning signals in the same number of that of the scanning lines of thedisplay panel H100. For example, in the case the input signals are videosignals in NTSC manner and the number of lines of the display panel is480, the scanning conversion part H105 outputs 480 effective scanninglines of 1 field=1 frame as to enable line-sequential driving in anon-interlaced way, from the NTSC signals which has about 240 effectivescanning beam lines for one field and produces one frame from 2 fields.

In this example, at the time of converting the interlace signals to theprogressive signals in the scanning conversion part, an interlaceprogressive conversion (IP conversion) circuit with configuration ofconverting the frame rate is employed.

In this example, in the case the input signals are interlace signals,the conversion to the progressive signals is carried out using such acircuit. The actual configuration for the IP conversion is illustratedin the FIG. 178. In this example, both of inter-field interpolation andinner field interpolation are employed for generation of the scanninginterpolating signals at the time of conversion of the interlace signalsto the progressive signals. In the FIG. 178, the reference number 17801is a signal movement detection part. At the time when the movement ofimage signals is wide, it is preferable to carry out inner fieldinterpolation and at the time when the movement of the image signals isnarrow, it is preferable to carry out inter-field interpolation, so thatthe movement of the image signals is detected by the movement detectionpart 17801 to determine the ratio of the blending the inter-fieldinterpolating signals and the inner field interpolating signals. Thereference number 17807 is an inter-field interpolation circuit, which isa circuit to determine scanning signals in the intervals of every theother scanning signals based on the scanning signals of a prior field,for example, of a field immediate before. More practically, the circuitemploys signals of relevant scanning of the field immediate before asthe scanning signals in the intervals of every the other scanningsignals. The reference number 17802 denotes a delay circuit for delayingand outputting the image signals to carry out inter-field interpolation.The reference number 17803 denotes an interpolation circuit, which is acircuit for generating the scanning signals for interpolation fromsignals of the delayed prior field sent from a delay circuit 17802. Thereference number 17808 denotes an inner field interpolation circuit,which is a circuit for generating the scanning signals in the intervalsof every the other scanning signals by blending computation of aplurality of other scanning signals, for example, of the foregoing everythe other scanning signals. The reference number 17804 denotes a delaycircuit for delaying and outputting the image signals to carry out innerfield interpolation. The reference number 17805 is an interpolationcircuit for producing the scanning signals for interpolation by blendingthe prior scanning signals outputted from the delay circuit 17804 andscanning with different delayed degrees, for example, scanning signalswhich are inputted without being delayed. The reference number 17806 isa blending circuit for determining the blending ratio of interpolationsignals from the interpolation circuit 17803 and the interpolationcircuit 17805 based on the signals from the movement detection circuit17801 and outputting the progressive signals. At the time of carryingout the conversion, the signals may be digital signals and a memory maybe employed for the delay circuit. Further, the configuration of the IPconversion is not limited to a hardware configuration but may beperformed by a software using a computation circuit. Also, only eitherof the inter-field interpolation and the inner field interpolation maybe carried out.

In this example, the scanning conversion part H105 includes a matrixcircuit to convert the decoded signals into RGB primary color signals,which are fluorescent material-emitting colors.

The luminance data sampling part H106 receives RGB primary color signalsfrom the scanning conversion part H105 and carries out sampling ofluminance data in the same number as that of pixels in every one line ofthe display panel H100 for RGB parallel 3-systems for every scanningline. In this example, since the color arrangement of the fluorescentmaterials is made to be RGB vertical stripes, the number of the pixelsfor every one line of the display panel H100 is ⅓ of thecolumn-direction wires.

The gamma conversion part H107 is correction means of gradationproperties installed in the RGB parallel 3-systems and turns thenon-linearity (gamma correction of CRT) which the video signal inputspreviously have back to linear property or corrects the non-linearity ofthe luminance modulation signals generated by the column-directionwiring modulation part and the luminescence quantity of the displaypanel H100. In the case the same correction degree is sufficient for theRGB 3-systems, it is not necessarily required to install the part in3-systems and correction may be carried out for signals of 1 system, forexample, luminance data to the column wire modulation part H101 whichwill be described later.

The primary data re-arrangement part H108 re-arranges luminance data ofrespective RGB 3-primary colors sent from the gamma conversion part H107in color arrangement order of the fluorescent materials of the displaypanel H100 and outputs the data as luminance data of 1-system to thecolumn wire modulation part H101. For the luminance data output to thecolumn wire modulation part H101, ON/OFF control to determine whetherthe output is performed or not is carried out based on the controlsignals EN0 from the system control part H111.

In order to display the image signals, in this example, the displaypanel H100 is driven by line-sequential scanning driving. That is, theluminance data is transferred to shift resistor means constituted ofresistors in the same number as that of the column wiring wires, whichthe column wire modulation part H101 comprises, during one scanningperiod of the image signals (it means the scanning period afterconversion of the signals in the same number as that of the lines of thedisplay panel H100 by the foregoing scanning conversion part and,hereafter, named as horizontal one cycle) and reads out the luminancedata from the shift resistor by the column wire drivers installed inrespective column wires before transfer of the luminance data of thenext horizontal one cycle is started and applies the driving intensitycorresponding to the luminance data to the respective column wiringwires simultaneously with all of the column wiring wires in the nexthorizontal one cycle.

By the shift resistor means, so-called serial-parallel conversion totransmit serial luminance data to respective column wire drivers inparallel is carried out.

Loading the luminance data in the shift resistor is carried out by ashift clock TM1 from the timing generation part H110 and loading thedata to the column wire driver part and the control of the output timingto the column wiring wires are carried out by trigger signals TM2 set inthe phase avoiding to the luminance data transferring timing to theshift resistor. Also, upon reception of the horizontal cycle clock TM3and the scanning starting trigger TM4 from the timing generation partH110, the row wire scanning part H102 successively supplies theselective voltage pulses almost equivalent to the horizontal one cycleto row wires one by one. That can be performed by installing, forexample, 1 bit shift resistors in the same number of that of the rowwiring wires.

The timing generation part H110 generates driving timing signals for therow wire scanning part H102 and the column wire modulation part H101and, other than that, generates timing signals necessary to operate thescanning conversion part H105 and luminance data sampling part H106,which are not shown in the figure. By the synchronizing signals from thevideo decoder part H104, various types of timing signals synchronizedwith the input video signals can be generated.

Since electron emitting devices of the line to which the row wireselective voltage pulses are applied emit electron beam corresponding tothe driving intensity applied from the column wires, excellent imagedisplay is made possible by setting the scanning starting trigger TM4 asto conform the luminance data of one horizontal cycle to be inputted tothe column wire modulation part H101 to the phase of the row wireselective voltage pulses.

The following four means may be performed as the method for applying thedriving intensity to each column wire corresponding to the luminancedata.

(1) to carry out pulse width (application duration) modulation ofconstant voltage corresponding to the luminance data.

(2) to carry out pulse width (application duration) modulation ofconstant current corresponding to the luminance data.

(3) to carry out amplitude modulation of voltage source outputcorresponding to the luminance data.

(4) to carry out amplitude modulation of current source outputcorresponding to the luminance data.

The following is description of these 4 means.

The method (1) employs a voltage power source means to apply column wiredriving potential to respective column wires and a pulse widthmodulation means (hereafter referred to PWM means) to change theduration of the time of applying the driving potential corresponding tothe luminance data for respective column wires.

The PWM means comprises, for example, a down-counter and counts to theextent of the luminance data read from the shift resistor means by acount clock whose one cycle is determined by dividing the duration ofapproximately one horizontal cycle or shorter by the number of desiredgradations and outputs the pulses from the starting count to thefinishing count, so that the method (1) can be performed.

The driving intensity corresponding to the luminance data can be appliedto the respective column wires by connecting the voltage source to thecolumn wires during the intervals of output pulses from the PWM meansand earthing it during the time beside the intervals.

By using SW means which switches ON/OFF application of the d.c.potential for constituting the voltage source, the driving driver partcan be materialized with a simple circuit and therefore, an economicaldriving circuit can be provided.

The method (2) is carried out by replacing the voltage source means forthe respective column wires for the method (1) with a current sourcemeans and the driving intensity corresponding to the luminance data canbe applied to the respective column wires by connecting the currentsource to the column wires during the intervals of output pulses fromthe PWM means and earthing it during the time beside the intervals.

This method is effective in the case the display panel H100 is made tohave high resolution and to be a wide screen. In the case the displaypanel H100 is made to have high resolution, the number of electronemission devices is increased and subsequently, in the driving methodrequiring line-sequential scanning driving, high electric current (thetotal of driving current of the electron emission devices of one line)flows in row wires at the time of selection. Depending on the resistancevalue of the row wires, the voltage drop due to the electric currentsometimes occurs. That is, in the driving by the voltage power source,the driving voltage to be applied to the electron emitting devices isdecreased owing to the effect of the wire voltage drop and consequentlythe luminance decrease is possibly caused. In the case of driving by theelectric current source, even if the wire voltage drop occurs, thedriving voltage to be applied to the electron emission devices is notchanged and thus this method is provided with an advantage that theluminance does not fluctuate.

In the method (1), the luminance gradation is performed by the PWMmeans. On the other hand in the method (3) the duration (the pulsewidth) during which the voltage power source is connected to the columnwires is set to be constant in stead of changing the pulse widthcorresponding to the luminance data, and the output voltage amplitude ofthe voltage power source is changed corresponding to the luminance data.

As the means for changing the output voltage amplitude, for example, D/Aconverters are installed in respective column wires and luminance datatransmitted to the shift resistor part for every horizontal cycle istransmitted to the D/A converters to be outputted.

In the case of employing the PWM means, the output pulse width iscounted by the frequency calculated by dividing approximately onehorizontal cycle period by the number of the luminance gradations,however in the case the display panel H100 is made to have a largescreen and high resolution and number of lines is increased, onehorizontal cycle is shortened and the PWM operation frequency isheightened. Also in the case the number of the gradations is increasedin order to improve the image quality, the PWM operation frequency isheightened, too.

On the other hand, in the method involving a process of changing theoutput voltage amplitude corresponding to the luminance data, theduration of driving the column wires is constant, so that the drivingfrequency of the column wire modulation part can considerably belowered.

The method (4) is carried out by replacing the voltage source means forthe respective column wires for the method (3) with a current sourcemeans and involves a process of changing the output current amplitude ofthe current source corresponding to the luminance data.

As same as the method (2), the method is effective in the case voltagedrop of the row wires is possible to occur.

In the foregoing methods (1) to (4), the relation of the drivingintensity corresponding to the respective luminance data and theluminescence quantities of the display panel H100 is possibly changed,the conversion characteristic of the gamma conversion part H107 isrequired to be changed corresponding to the luminescence characteristicsof the respective driving methods.

For example, in the case of PWM modulation, the luminance data and theluminescence quantity have an approximately linear relation andtherefore it is proper to provide the gamma conversion part H107 with aconversion characteristic as to cancel the gamma characteristic added tothe video signals.

Further, the electron emission devices of the display panel H100 hasdriving voltage-electron emission quantity characteristic as shown inthe FIG. 173 and the driving voltage-luminescence quantitycharacteristic is almost similar. For that, in the case of the luminancegradation is performed by the voltage amplitude modulation by the method(3), it is proper to provide the gamma conversion part H107 with aconversion characteristic in consideration of such a characteristic.

The characteristic curves illustrated in the FIG. 173 are typical curvesof (emission current Ie) vs. (device application voltage Vf) and (devicecurrent If) vs. (device application voltage Vf) of the electron emissiondevices. The emission current Ie is remarkably small as compared withthe device current If and since it is difficult to show in the samescale and these characteristics are changed by altering the designparameters such as the size and the shape of the devices, two graphs areillustrated based on respective arbitrary unit.

The devices employed for the display apparatus has the following threecharacteristics relevant to the emission current Ie.

At first, when a certain voltage (named it as threshold voltage Vth) orhigher is applied to an device, emission current Ie sharply increases,whereas when voltage lower than the threshold voltage Vth is applied,emission current Ie is scarcely detected. In other words, the devicesare non-linear devices having a clear threshold voltage Vth in terms ofemission current Ie.

Secondly, since the emission current Ie changes depending on the voltageVf applied to the devices, the extent of the emission current Ie can becontrolled by the voltage Vf.

Thirdly, since the response speed of the current Ie emitted from thedevices in relation to the voltage Vf applied to the device is quick,the charge quantity of the electrons emitted out of the devices can becontrolled by duration of the voltage Vf application.

Owing to the above described characteristics, the surface conductiontype electron emission devices are preferably employed for the displayapparatus. For example, in a display apparatus in which a large numberof devices are formed corresponding to the pixels of the display screen,display is enabled by sequential scanning of the display screen byutilizing the first characteristic. That is, voltage not lower than thethreshold voltage Vth corresponding to the desired luminescenceluminance is properly applied to driving devices, whereas voltage lowerthan the threshold voltage Vth is applied to devices in non-selectedstate. By sequentially changing the devices to be driven, display can becarried out by sequential scanning of the display screen. The gradationdisplay can also be carried out by utilizing the second or the thirdcharacteristic, based on which the luminescence luminance can becontrolled.

Further, besides the driving methods (1) to (4), driving methodsemploying these methods in combination may also be carried out. Forexample, for performing gradation display, both of the PWM means and theamplitude modulation means are installed as to partly carry out thegradation display by amplitude modulation to increase the number of thegradations possible to be displayed or to be slower the PWM clockfrequency. Or, both of the PWM means and the amplitude modulation meansare installed as to carry out the gradation display corresponding to theluminance data and as to carry out brightness adjustment and coloradjustment by amplitude modulation. Contrary, the gradation display maybe carried out by the amplitude modulation and brightness adjustment andcolor adjustment by the PWM modulation. Moreover, both of the voltagesource output and the current source output are installed and drivingmay be carried out by the voltage source until the potential determinedby the voltage source output voltage and then by the current source. Bysuch a driving method, the temporarily rise up characteristic at thetime of driving application can be improved.

This example is further provided with an average luminance leveldetection part H109 for carrying out automatic brightness controlfunction (hereafter named as ABL). The function is for controlling theaverage luminance of the display panel not to exceed a certain level inorder to suppress the power consumption of the image display apparatusor suppressing the temperature increase of the light emitting face. Theaverage luminance level detection part H109 detects the averageluminance level during one frame displayed on the display panel H100from the luminance data outputs outputted from the gamma conversion partH107 and transmits the detection signals DT5 to a system control partH111. The system control part 111 is a part controlling the system ofthe panel driving part illustrated in the FIG. 169 and comprises CPU, areset means for stably raising CPM, ROM programmed with CPU drivingregulation programs, an IO means for regulating the respective drivingstates, for example, controlling ON/OFF control of the outputs of thecolumn wire modulation part H101 with binary values and takinginstruction data from the user I/F in the CPU, D/A conversion means forregulating the operating states of respective parts from wide ranges,RAM for saving the data of the D/A conversion means, a back-up memoryfor saving the data after power source OFF and regenerating the priorstate at the time of next power source ON as it was before reading out,and an A/D conversion means for monitoring the ABL and the respectiveoperating states.

In this example, the system control part H111 outputs a control signalCNT1 for varying the respective column wire driving quantities from thecolumn wire modulation part H101 and also outputs EN1, which is anON/OFF signal for controlling whether the column wire driving output isoutputted or not. The column wire modulation part H101 detects theamplitude value of the pulsed voltage generated in the column wiresowing to the column wire driving quantities and transmits the detectionsignal DT1 to the system control part H111.

In this case, the control signal CNT1 alters the output voltage of thevoltage source simultaneously to all of the column wires in the case ofconnecting the column wires to the current source and alters the outputcurrent of the current source simultaneously to all of the column wiresin the case of connecting the column wires to the current source.Alternatively, not simultaneously to all of the column wires, thealteration may be carried out separately for column wires of R, columnwires of G, and column wires of B by system of CNTI for three primarycolor RGB.

Further, the system control part H111 outputs a control signal CNT2 forvarying the respective row wire selective potential from the row wiremodulation part H102 and beside that, outputs EN2, which is an ON/OFFsignal for controlling whether the row wire selective voltage pulses isoutputted or not. The row wire modulation part H102 detects the row wireselective potential and transmits the detection signal DT2 to the systemcontrol part H111. In this case, the control signal CNT2 controls thepotential to be applied to the row wires at the time of selection andthe potential to the row wires is made controllable also atnon-selection time by installation of 2 systems for generating CNT2.

Furthermore, the system control part H111 outputs a control signal CNT3for varying the degree of high voltage output voltage from the highvoltage generation part H103. The high voltage generation part H103detects the high voltage output voltage and transmits the detectionsignal DT3 to the system control part H111. ABL driving can be performedby utilizing CNT1 which varies the column wire driving quantities. Thatis, the average luminance quantity of the display panel H100 issuppressed by monitoring the detection signal DT5 from the averageluminance level detection part H109 by the system control part H111 andcarrying out no control of the column wire driving quantity in the casethe average luminance level is low and decreasing the column wiredriving quantity by CTN1 in the case the average luminance level is at acertain level or higher.

Also in the case the column wire driving part comprises a voltagesource, the ABL driving can be achieved in the same manner by utilizingthe control signal CNT2 which varies the row wire selective potential.

The method how the detection signal DT5 from the average luminance leveldetection part H109 is utilized for the ABL driving is described aboveand the method is not restricted to that but may be carried out byutilizing the detection value of the average current flowing in thedisplay panel H100 from the high voltage generation part H103.

An example employing the method of controlling the driving quantity ofelectron emission devices of the display panel H100 as the luminancesuppressing means is also described and the method is not restricted tothat and luminance suppression can be carried out, for example, bycontrolling the outputs of the high voltage generation part H103 orcontrolling the extent of the luminance data to be inputted to thecolumn wire modulation part.

The image display apparatus illustrated in the FIG. 169 is furtherprovided with a main power source part H121, a S power source part H122,and a K power source part H123. The main power source part H121 isprovided with a power switching means not shown in the figure and at thetime of ON of the switching means, receiving AC input, the main powersource part outputs a power output PS0 to the S power source part H122,the K power source part H123 and the high voltage generation part H103.The power output PS0 is ON/OFF-controlled as to be sent or not by thecontrol signal PCN0 from the system control part H111. The main powersource part H121 also outputs the detection signal DT4 for monitoringthe AC input and transmits it to the system control part H111.

The main power source part H121 further outputs the power output PSSwhich is one power supply line to a block S constituted of the systemcontrol part H111 and the user I/F part H112. The power output PSSsupplied electricity enough to drive the user I/F part H112 and theminimum part of the system control part H111 which receives the inputfrom the user I/F part H112 and is capable of processing the input fromthe user I/F part H112. In this case, the state that driving is carriedout only by the power output PSS is named as a standby mode. In thestandby mode, the remote control reception part included in the user I/Fpart H112 is active and the system can be driven by user instruction.

The S power source part H122 outputs the power output PS1, which is apower supply line to a block B1 constituted of the video decoder partH104, the scanning conversion part H105, the luminance data samplingpart H106, the gamma conversion part H107, the primary color datarearrangement part H108, the average luminance level detection partH109, and the timing generation part H110 and to the block S. The poweroutput PS1 is ON/OFF-controlled as to be sent or not by the controlsignal PCN1 from the system control part H111.

The K power source part H123 outputs the power output PS2, which is apower supply line, to the block B2 constituted of the column wiremodulation part H101 and the row wire scanning part H102. The poweroutput PS2 is ON/OFF-controlled as to be sent or not by the controlsignal PCN2 from the system control part H111.

The output PS3 from the high voltage generation part H103 isON/OFF-controlled as to be sent or not by the control signal PCN3 fromthe system control part H111.

The system control part H111 regulates the driving procedure at the timeof rise up of the power source, the driving procedure at the time offall of the power source, and the driving procedure at the time ofabnormality. The display panel H100 is provided with a rated value ofthe high voltage application and rated value of application voltage tothe electron emission device in the display panel H100. If the voltageexceeds the rated values, the display panel H100 is possibly broken, sothat the voltage is prevented from exceeding even at the time of powerrise up or power fall or occurrence of unexpected incidents.

The processing procedure at the time of power rise up is illustrated inthe FIG. 170.

At the time of power rise up, there are a mode which is started byturning on the power source SW in the main power source part H121 and amode which is turned on from the standby mode. When the power source SWis turned on, AC power is supplied to the main power source part H121and the main power source part H121 supplies the power output PSS to theblock S. The reset means in the system control part H111 drives the CPUafter stabilization of the power output PSS. The CPU down-loads programsfrom the ROM housing the driving programs and initializes the systemaccording to the programs.

At the time of initialization, the system control part H111 sets thepower output control signals PCN0 to PCN3 in OFF state, sets theluminance data output enabling signal EN0 to the column wire modulationpart H101, the driving quantity output enabling signal EN1 from thecolumn wire modulation part H101, and selective pulse output enablingsignal EN2 from the row wire scanning part in OFF state, and sets thesignals CNT1 to CNT3 for controlling the high voltage output values,column wire driving quantity, row wire selective potential in theminimum output value state (step S100).

In the standby mode, the initialization is already finished. Oncompletion of the initialization, the system control part H111 turns thepower output control signals PCN0, PCN1 on to start the block S andblock B1. Consequently, the main electricity supply line PS0 isoutputted from the main power source part H121 and the power output PS1is outputted from the S power supply part H122. After the PSI issupplied, the system control part H111 reads out the driving conditiondata (the high voltage output value setting data, the column wiredriving quantity setting data, the row wire selective potential settingdata, etc.) of the display panel H100 from the back-up memory builttherein. By inputting the PS1 to the block B1, the part for processingthe inputted video signals is started for driving (step S101).

The system control part H111 turns the power output control signal PCN2on to drive the block B2 after waiting that the block B1 driving isstabilized and also outputs CNT1, CNT2 signals to make outputs of thecolumn wire driving quantity and the row wire selective potential readyby transmitting the signal to the D/A converter means containing thecolumn wire driving quantity setting data and the row wire selectivepotential setting data and further initializes data of all of the shiftresistors in the column wire modulation part H101 and the row wirescanning part H102 to be zero (step S102).

After it is confirmed that the output preparation of the column wiredriving quantity and the row wire selective potential is normallycarried out by the column wire potential abnormality monitoring signalDT1 and the row wire potential abnormality monitoring signal DT2, thesystem control part H111 puts the luminance data output enabling signalEN0 to the column wire modulation part H101 in output state, and thenputs the driving quantity output enabling signal EN1 from the columnwire modulation part H101 in output state, and finally the selectivepulse output enabling signal EN2 from the row wire modulation part H101in output state (step S103).

The system control part H111 turns the power output control signal PCN2on, transmits the high voltage output value setting data to the D/Aconverter means to output a desired high voltage, and sets the CNT3 at aprescribed value. In order to softly start the rise up of the highvoltage, the data transmission to the D/A converter means is carried outto set CNT3 at a prescribed value in steps by moderately increasing thevoltage to the prescribed value from the minimum value at a certain timeconstant but not instantaneously to the prescribed value (step S104).

By above describe procedure, the rise up is completed. After that, DT1to DT4 are monitored and if abnormality occurs, the mode is shifted tothe abnormality processing mode (step S105). Also, if electric power OFFdemand is instructed, the mode is shifted to the power OFF mode (stepS106). In the FIG. 170, the description is restricted only to the powerrise up sequence and therefore the contents are limited to the matterrelevant to the power rise up sequence and it is no need to say that thesystem control part H111 can carry out image adjustment corresponding tothe demands of a user and has other functions.

The processing procedure at the time of fall is illustrated in the FIG.171. When the system control part H111 receives an instruction signal ofpower OFF from a user by a remote controller through a user I/F partH112, the system control part H111 is puts in power OFF mode. At firstin order to carry out fall of the high voltage power source, the highvoltage output value setting control signal CNT3 is made to be theminimum and turn off the power output control signal PCN3 (step S200).

The system control part H111 puts the selective pulse output enablingsignal EN2 from the row wire scanning part in OFF state and then putsthe driving quantity output enabling signal EN1 from the column wiremodulation H101 in OFF state and next the luminance data output enablingsignal EN0 to the column wire modulation part H101 in OFF state (stepS201).

Following that, to carry out fall of the block B2, the system controlpart H111 sets two signals of column wire driving quantity and the rowwire selective potential control signals CNT1, CNT2 to be the minimumand turns the power output control signal PCN2 off (step S202).

After the instruction of fall of the high voltage power source and thedisplay panel driving part, the mode is put in a standby mode, so thatthe system control part H111 turns the power output control signal PCN1and power output control signal PCN0 off (step S203). If power ON demandis instructed, the mode is shifted to the power ON mode (step S106).

By the foregoing procedure, the mode can be put in a standby mode byreceiving only a restarting signal from a remote controller of a user orthe like.

The processing procedure at the time of abnormality is illustrated inthe FIG. 172. In this case the time of abnormality means the followingthree cases.

(A) in the case of absence of AC input;

(B) high power source abnormality; and

(C) driving voltage abnormality of electron emission devices.

At first, occurrence of the above described abnormality is distinguished(step S300). The following will successively describe the driving todeal with the respective cases of abnormality.

(A) Regarding the Processing Procedure in the Case of Absence of ACInput:

Originally, it is desirable for the image display apparatus to fallaccording to the regulated sequence as described above by theinstruction of power OFF by a user, however sometimes the apparatus isput in fall in undesirable situation, for example, power failure andcoming off of an AC cable.

In the FIG. 169, the system control part H111 monitors the AC inputalteration by the input AC potential detection signal DT4 from the mainpower source part H121. In the case the input AC potential is loweredless than a prescribed value, it is determined that abnormal stateoccurs by DT4 before the driving of the main power source H121 isstopped and the system control part H111 instructs the shift to thestandby mode.

At first, the system control part turns the power output control signalPCN3 off in order to swiftly turn off the high voltage power source(step S301) and simultaneously puts the enabling signals EN0 to EN2 inOFF state in order to swiftly turn off the outputs of the row wirescanning part and the column wire part (step S302).

Secondly, the system control part makes the high voltage output valuesetting control signal CNT3, which is the remaining of the fallingprocess of the high voltage generation part H103 and the block B2, to beminimum and sets the column wire driving quantity and the row wireselection potential control signal CNT1, CNT2 to be minimum. Then turnsthe power output control signal PCN2 off (step S303).

At that time, the system control part H111 again confirm the input ACpotential before the shift to the standby mode (step S304). If the inputAC is restored to a normal state, re-starting process is carried out(steps S305, S306) and if the AC input to the main power source partH121 is not restored, the shift to the standby mode is done (step S307).In this case, a user has to require restarting to put the apparatus inON state again.

(B) Regarding the Processing Procedure in the Case of High Voltage PowerAbnormality:

In the FIG. 169, the system control part H111 monitors the voltagepotential alteration by the high voltage potential detection signal DT3from the high voltage generation part H103. In the case the high voltagepotential is increased higher than the prescribed value or thedifference from the instructed value by CNT3 becomes wide, it isdetermined that the high voltage generation part H103 is in abnormalstate and the system control part H111 carried out processing fordealing with the abnormality.

At first, the system control part turns the power output control signalPCN3 off in order to swiftly turn off the high voltage power source(step S308) and simultaneously puts the enabling signals EN0 to EN2 inOFF state in order to swiftly turn off the outputs from the row wirescanning part and the column wiring part (step S309).

Next, the system control part makes the high voltage output valuesetting control signal CNT3, which is the remaining of the fallingprocess of the high voltage generation part H103 and the block B2, bethe minimum and sets the column wire driving quantity and row wireselective potential control signal CNT1, CNT2 to be the minimum and thenturns the power output control signal PCN2 off (step S310).

Since this abnormality is an apparatus disorder, the system control partH111 writes the abnormality mode data for informing that the highvoltage generation part H103 falls into abnormal state in the back-upmemory before the mode is shifted to the standby mode (step S311). Then,the mode is shifted to the standby mode. Consequently, at the time ofthe restoration, the trouble mode can be known by confirming the back-upmemory.

(C) Driving Voltage Abnormality of the Electron Emission Devices:

The driving voltage abnormality of the electron emission devices can besupposed to be derived from either row wire selective potential (in thecase of regulating the potential of non-selective time, thenon-selective potential is included) or the column wire applicationpotential (in the case of regulating the potential of non-applicationtime, the non-application potential is included).

In the FIG. 169, the system control part H111 monitors the drivingvoltage abnormality by the amplitude value detection signal DT1 of thepulsed voltage generated in the column wires from the column wiremodulation part H101 and the row wire selective potential detectionsignal DT2 from the row wire modulation part H102.

In the case the column wire driving voltage amplitude value is increasedhigher than the prescribed value or in the case the difference from theinstruction value by the CNT1 becomes wide, it is determined that thecolumn wire modulation part H101 is in abnormal state and the systemcontrol part H111 carries out processing for dealing with theabnormality.

Further, in the case the row wire selective potential is increasedhigher than the prescribed value or in the case the difference from theinstruction value by the CNT2 becomes wide, it is determined that therow scanning modulation part H102 is in abnormal state and the systemcontrol part H111 carries out processing for dealing with theabnormality. In the case of abnormality of the column wire modulationpart H101 and abnormality of the row wire scanning part H102, theprocessing procedure for dealing with the abnormality is same and thesystem control part simultaneously puts the enabling signals EN0 to EN2in OFF state in order to swiftly turn off the outputs from the row wirescanning part and the column wiring part (step S312) and turns the poweroutput control signal PCN3 off in order to swiftly turn off the highvoltage power source (step S313).

Next, the system control part makes the high voltage output valuesetting control signal CNT3, which is the remaining of the fallingprocess of the high voltage generation part H103 and the block B2, bethe minimum and sets the column wire driving quantity and row wireselective potential control signal CNT1, CNT2 to be the minimum and thenturns the power output control signal PCN2 off (step S310).

Since this abnormality is an apparatus disorder, the system control partH111 writes the abnormality mode data for informing that either columnwire modulation part H101 or the row wire scanning part H102 falls intoabnormal state in the back-up memory before the mode is shifted to thestandby mode (step S311). Then, the mode is shifted to the standby mode.Consequently, at the time of the restoration, the trouble mode can beknown by confirming the back-up memory.

As described above, application of high voltage out of the rated valueto the display panel H100 and application of driving application voltageout of the rated value to the electron emission devices of the displaypanel H100 can be prevented by the driving procedure of rise time of thepower source, the driving procedure of fall time of the power source,and the driving procedure at the time of abnormality.

(34th Configuration)

An application example of the present invention to various types ofapparatus will be described below.

The FIG. 174 is a block figure illustrating an example of amultifunctional display apparatus constituted in such a manner thatimage information supplied from various image information sources, theforemost of which is a television broadcast, can be displayed on adisplay panel employing the surface conduction type electron emissiondevices as electron beam sources according to the foregoing respectiveconfigurations. In the figure, the reference number 2100 denotes adisplay panel, the reference number 2101 denotes a driving circuit ofthe display panel, the reference number 2102 denotes a displaycontroller, the reference number 2103 denotes a multiplexer, thereference number 2104 denotes a decoder, the reference number 2105denotes an input/output interface circuit, the reference number 2106denotes a CPU, the reference numbers 2108, 2109, and 2110 denoteimage-memory interface circuits, the reference number 2111 denotes animage-input interface circuit, the reference numbers 2112 and 2113denote TV signal receiving circuits, and the reference number 2114denotes an input/output part.

In the case this display apparatus receives a signal containing bothvideo information and the audio information as in the manner of, forexample, television signal, audio is of course reproduced simultaneouslywith the video display and those which are widely used in relevantfields may be employed for circuits and speakers related to thereception, separation, reproduction, processing and storage of the audioinformation.

The functions of respective parts will be described in line with theflow of the image signal.

At first, the TV signal receiving circuit 2113 is for receiving TV imagesignals transmitted using a wireless transmission system of, forexample, radio waves and spatial optical communication. The system ofthe TV signal reception is not specifically limited and examples of thesystem include NTSC system, PAL system, SECAM system, etc. TV signalscomprising a greater number of scanning lines (e.g. so-called highdefinition TV employing MUSE system) are signal source suitable forexploiting the advantages of the above described display panel suited toenlargement of the screen surface area and increase in the number ofpixels. The TV signals received by the TV signal receiving circuit 2113are outputted to the decoder 2104.

TV signal receiving circuit 2112 is for receiving TV image signalstransmitted by a cable transmission system using coaxial cables oroptical fibers. As in the case of the TV signal receiving circuit 2113,the systems of TV signals to be received is not specifically limited andthe TV signals received by this circuit are also outputted to thedecoder 2104.

The image-input interface circuit 2111 is for accepting the imagesignals supplied from an image-input apparatus such as a TV camera, animage reading scanner, and the likes and the accepted image signals areoutputted to the decoder 2104. The image-memory interface circuit 2110is for accepting the image signals stored in the a video tape recorder(hereafter abbreviated to VTR) and the accepted image signals areoutputted to the decoder 2104. The image-memory interface circuit 2109is for accepting the image signals stored in a video camera and theaccepted image signals are outputted to the decoder 2104.

The image-memory interface circuit 2108 is for accepting the imagesignals from an apparatus storing still-picture data such as so-calledstill-picture disk and the accepted still-picture data is outputted tothe decoder 2104. The input/output interface circuit 2105 is a circuitfor connecting this display apparatus and an external computer, computernetwork, or an output apparatus such as a printer. It is of coursepossible to input/output image data, character data and graphicinformation and, depending on the case, it is possible to input/outputcontrol signals and numerical data between the CPU 2106, with which thisdisplay apparatus is equipped, and an external unit.

The image generating circuit 2107 is for generating display image databased on image data and character/graphic information sent from anexternal unit through the input/output interface circuit 2105 or basedon image data and character/graphic information outputted by the CPU2106. The circuit is internally provided with, for example, rewritablememory for accumulating image data or character/graphic information, aread-only memory in which image patterns corresponding to charactercodes are stored and circuits necessary for generating images, such as aprocessor for executing image processing. The display image datagenerated by the circuit is outputted to the decoder 2104 and, in somecases, the display image data may be outputted to external computernetwork or a printer through an input/output interface circuit 2105. Theimage information processing circuit employed for this example comprisesthe decoder 2104, the multiplexer 2103, and the image generating circuit2107.

The CPU 2106 mainly carries out operation relevant to driving control ofthe display apparatus, producing, selecting and editing of displayimages, and the likes. For example, the CPU outputs control signals tothe multiplexer 2103 to suitably select or combine image signals to bedisplayed on the display panel. At that time, the CPU generates controlsignals for the display panel controller 2102 corresponding the imagesignals to be displayed and suitably controls the driving of the displayapparatus, such as the screen display frequency, the scanning method(e.g. interlaced or non-interlaced) and the number of the scanning linesof one screen. Further, the CPU 2106 outputs image data andcharacter/graphic information directly to the image generating circuit2107 or makes access to the external computer or a memory through theinput/output interface circuit 2105 to input image data andcharacter/graphic information directly to the image generating circuit2107.

It is no need to say that the CPU 2106 may also be used for purposedother than these. For example, the CPU may directly be applied to afunction for generating and processing information as in the manner of apersonal computer or a word processor. Alternatively, the CPU may beconnected to an external computer network through the input/outputinterface circuit 2105, as described above, so as to perform anoperation such as numerical computation in cooperation with the externalequipment.

The input unit 2114 is for allowing a user to enter instructions,programs or data into the CPU 2106 and examples are a keyboard and amouse, various other input devices such as a joystick, a bar codereader, a voice recognition unit, and the likes.

The decoder 2104 is a circuit for decoding various image signals sentfrom 2107, or 2113 into three primary color signals or into luminancesignals and I signals and Q signals. It is desirable for the decoder2104 to be internally equipped with an image memory as indicated by thedashed line in the figure. That is for the purpose of handlingtelevision signals which require an image memory when performing thedecoding, as in a MUSE system, by way of example. Providing the imagememory is advantageous in that display of a still picture is facilitatedand in that, in cooperation with the image generating circuit 2107 andthe CPU 2106, editing and image processing such as thinning out ofpixels, interpolation, enlargement, reduction and synthesis arefacilitated.

The multiplexer 2103 is for suitably selecting the display image basedon control signals sent from the CPU 2106. More specifically, themultiplexer 2103 selects desired image signals among the decoded imagesignals sent from the decoder 2104 and outputs the selected signals tothe drive circuit 2101. In that case, by changing over and selecting theimage signals within the display time of one screen, one screen can bedivided into a plurality of areas and images differing depending on theareas can be displayed as in the manner of so-called split-screentelevision.

The display panel controller 2102 is a circuit for controlling operationof the drive circuit 2101 based on the control signals sent from the CPU2106. With regard to the basic operation of the display panel, forexample, the display panel controller outputs signals for controllingthe operating sequence of a driving power source (not shown in thefigure) for the display panel to the drive circuit 2101. In relation tothe method of driving the display panel, the display panel controlleroutputs signals for controlling, say, the screen display frequency orthe scanning method (interlaced or non-interlaced) to the drive circuit2101. Further, in some cases, the display panel controller outputscontrol signals relating to adjustment of image quality such asluminance of displayed images, contrast, tone, and sharpness to thedrive circuit 2101.

The drive circuit 2101 is for generating driving signals to be appliedto the display panel 2101 and is driven based on the image signals sentfrom the multiplexer 2103 and the control signals sent from the displaypanel controller 2102.

The functions of respective parts are described above and using theconfiguration exemplified in the FIG. 174, image information sent from avariety of image information sources can be displayed on the displaypanel 2100 in the present display apparatus. In other words, variousimage signals, the foremost of which are television broadcast signals,are decoded by the decoder 2104, suitably selected by the multiplexer2103, and transmitted to the drive circuit 2101. On the other hand, thedisplay controller 2102 generates control signals for controlling theoperation of the drive circuit 2101 corresponding to the image signalsto be displayed.

The drive circuit 2101 applies drive signals to the display panel 2100based on the image signals and the control signals. Consequently, animage is displayed on the display panel 2100. The series of theoperations are under the overall control of the CPU 2106.

Further, in this display apparatus, attributed to the contribution ofthe image memory built in the decoder 2104, the image generating circuit2107, and the CPU 2106, it is made possible not only to display imageinformation selected from a plurality of items of image information butalso to perform image processing such as enlargement, reduction,rotation, movement, edge emphasis, thinning-out, interpolation, colorconversion, and aspect ratio conversion and image editing such assynthesis, elimination, connection, replacement, and fitting.

Furthermore, though not specifically mentioned in the description ofthis example, it is permissible to provide a circuit for exclusive usefor performing processing and editing with regard also to the audioinformation in the same manner as the foregoing image processing and theimage editing.

Accordingly, the display apparatus of the present invention is capableof being provided with various functions in a single unit, such as thefunctions of TV broadcast display equipment, office terminal equipmentsuch as television conference terminal equipment, image editingequipment for dealing with still pictures and motion pictures, computerterminal equipment, and word processors, games, and the likes. Thus, thedisplay apparatus has a wide range of application for industrial andcivil use.

The illustrated figure merely shows an example of the configuration ofthe display apparatus employing a display panel for which surfaceconduction type electron emission devices are used as electron beamsources and the apparatus is not limited to this configuration. Forexample, circuits related to functions unnecessary for the particularpurpose of use may be eliminated from the constituent devicesillustrated in the figure. Contrary, depending on the purpose of use,constituent devices may be added. For example, in the case the displayapparatus of the present invention is applied to a television telephone,it would be suitable to add a transmitting/receiving circuit comprisinga television camera, an audio microphone, a luminaire, and a modem tothe constituent devices.

In the display apparatus of the present invention, especially thedisplay panel comprising the surface conduction type electron emissiondevices as electron beam sources can easily be thinned, so that thedepth of the whole display apparatus body can be thin. In addition tothat, the display panel comprising the surface conduction type electronemission devices as electron beam sources is easily made to be a widescreen, provided with high luminance, and excellent in angularproperties of visual field, so that the display apparatus is capable ofdisplaying vivid and impressive images with excellent visibility.

As described above, the present invention can provide an image formingapparatus capable of dealing with the screen enlargement and comprisingconfiguration giving excellent display quality.

1. An image formation apparatus comprising: a substrate on which aplurality of wires for connecting electron emission devices are placed;a substrate on which an image formation material for forming images byradiation of electrons emitted from the electron emission devices isplaced; spacers placed between said substrates; and getters, whereinsaid spacers are placed on some but not all of said wires, and saidgetters are placed on those of said wires without spacers.
 2. An imageformation apparatus comprising: a substrate on which a plurality ofwires for connecting electron emission devices are placed; a substrateon which an image formation material for forming images by radiation ofelectrons emitted from the electron emission devices is placed; aplurality of spacers placed between said substrates; and getters,wherein said spacers are placed on said wires, and said getters areplaced on said wires between said spacers.
 3. An electron beam sourcesubstrate comprising: a plurality of electron emission devices; wiresconnected to said electron emission devices; and getters, wherein saidgetters are placed on said wires, and both said getters and said wireshave an arch-shaped cross-section.
 4. The electron beam source substrateaccording to claim 3, wherein said getters are non-evaporation typegetters.
 5. The electron beam source substrate according to claim 3,wherein said getters placed on said wires are narrower than said wires.6. An image formation apparatus comprising, within an enclosure: asubstrate on which electron emission devices, wires connected to theelectron emission devices and getters are provided; and an imageformation material for forming images by radiation of electrons emittedfrom said electron emission devices, wherein said getters are placed onsaid wires, and both said getters and said wires have an arch-shapedcross-section.
 7. The image formation apparatus according to claim 6,wherein said getters are non-evaporation type getters.
 8. The imageformation apparatus according to claim 6, wherein said getters placed onsaid wires are narrower than said wires.
 9. An image forming apparatusincluding a faceplate on which fluorescent materials and black materialsare provided, and a rear plate disposed opposite to said faceplate, onwhich electron emitting devices are provided, wherein electron beamsemitted from electron emitting portions of said electron emittingdevices have an intensity distribution, and wherein, in order toirradiate said fluorescent materials with a higher energy region of theelectron beams and irradiate said black materials with a lower energyregion of the electron beams, the electron emitting portions of saidelectron emitting devices are respectively placed below said blackmaterials.